]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/netinet/ip_input.c
xnu-3247.1.106.tar.gz
[apple/xnu.git] / bsd / netinet / ip_input.c
index b71b165d4cb95ab9cf425e0be5c22648c64f9a10..994bbf8a3736c4f924ff1b71e1749b4d6c03c899 100644 (file)
@@ -1,8 +1,8 @@
 /*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2015 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
- * 
+ *
  * This file contains Original Code and/or Modifications of Original Code
  * as defined in and that are subject to the Apple Public Source License
  * Version 2.0 (the 'License'). You may not use this file except in
  * unlawful or unlicensed copies of an Apple operating system, or to
  * circumvent, violate, or enable the circumvention or violation of, any
  * terms of an Apple operating system software license agreement.
- * 
+ *
  * Please obtain a copy of the License at
  * http://www.opensource.apple.com/apsl/ and read it before using this file.
- * 
+ *
  * The Original Code and all software distributed under the License are
  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
@@ -22,7 +22,7 @@
  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  * Please see the License for the specific language governing rights and
  * limitations under the License.
- * 
+ *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 /*
  * SUCH DAMAGE.
  *
  *     @(#)ip_input.c  8.2 (Berkeley) 1/4/94
- * $FreeBSD: src/sys/netinet/ip_input.c,v 1.130.2.25 2001/08/29 21:41:37 jesper Exp $
+ */
+/*
+ * NOTICE: This file was modified by SPARTA, Inc. in 2007 to introduce
+ * support for mandatory and extensible security protections.  This notice
+ * is included in support of clause 2.2 (b) of the Apple Public License,
+ * Version 2.0.
  */
 
 #define        _IP_VHL
 #include <sys/kernel.h>
 #include <sys/syslog.h>
 #include <sys/sysctl.h>
+#include <sys/mcache.h>
+#include <sys/socketvar.h>
+#include <sys/kdebug.h>
+#include <mach/mach_time.h>
+#include <mach/sdt.h>
+
+#include <machine/endian.h>
+#include <dev/random/randomdev.h>
 
 #include <kern/queue.h>
 #include <kern/locks.h>
+#include <libkern/OSAtomic.h>
+
+#include <pexpert/pexpert.h>
 
 #include <net/if.h>
 #include <net/if_var.h>
 #include <net/if_dl.h>
 #include <net/route.h>
 #include <net/kpi_protocol.h>
+#include <net/ntstat.h>
+#include <net/dlil.h>
+#include <net/classq/classq.h>
+#include <net/net_perf.h>
+#if PF
+#include <net/pfvar.h>
+#endif /* PF */
 
 #include <netinet/in.h>
 #include <netinet/in_systm.h>
 #include <netinet/in_var.h>
+#include <netinet/in_arp.h>
 #include <netinet/ip.h>
 #include <netinet/in_pcb.h>
 #include <netinet/ip_var.h>
 #include <netinet/ip_icmp.h>
-#include <sys/socketvar.h>
-
 #include <netinet/ip_fw.h>
 #include <netinet/ip_divert.h>
-
 #include <netinet/kpi_ipfilter_var.h>
-
-/* needed for AUTOCONFIGURING: */
 #include <netinet/udp.h>
 #include <netinet/udp_var.h>
 #include <netinet/bootp.h>
+#include <netinet/lro_ext.h>
 
-#include <sys/kdebug.h>
-
-#define DBG_LAYER_BEG          NETDBG_CODE(DBG_NETIP, 0)
-#define DBG_LAYER_END          NETDBG_CODE(DBG_NETIP, 2)
-#define DBG_FNC_IP_INPUT       NETDBG_CODE(DBG_NETIP, (2 << 8))
+#if DUMMYNET
+#include <netinet/ip_dummynet.h>
+#endif /* DUMMYNET */
 
+#if CONFIG_MACF_NET
+#include <security/mac_framework.h>
+#endif /* CONFIG_MACF_NET */
 
 #if IPSEC
 #include <netinet6/ipsec.h>
 #include <netkey/key.h>
-#endif
+#endif /* IPSEC */
 
-#include "faith.h"
-#if defined(NFAITH) && NFAITH > 0
-#include <net/if_types.h>
-#endif
-
-#if DUMMYNET
-#include <netinet/ip_dummynet.h>
-#endif
+#define        DBG_LAYER_BEG           NETDBG_CODE(DBG_NETIP, 0)
+#define        DBG_LAYER_END           NETDBG_CODE(DBG_NETIP, 2)
+#define        DBG_FNC_IP_INPUT        NETDBG_CODE(DBG_NETIP, (2 << 8))
 
 #if IPSEC
 extern int ipsec_bypass;
 extern lck_mtx_t *sadb_mutex;
-#endif
-
-int rsvp_on = 0;
-static int ip_rsvp_on;
-struct socket *ip_rsvpd;
-
-int    ipforwarding = 0;
-SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW,
-    &ipforwarding, 0, "Enable IP forwarding between interfaces");
 
-static int     ipsendredirects = 1; /* XXX */
-SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW,
-    &ipsendredirects, 0, "Enable sending IP redirects");
+lck_grp_t      *sadb_stat_mutex_grp;
+lck_grp_attr_t *sadb_stat_mutex_grp_attr;
+lck_attr_t     *sadb_stat_mutex_attr;
+decl_lck_mtx_data(, sadb_stat_mutex_data);
+lck_mtx_t      *sadb_stat_mutex = &sadb_stat_mutex_data;
+#endif /* IPSEC */
 
-int    ip_defttl = IPDEFTTL;
-SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW,
-    &ip_defttl, 0, "Maximum TTL on IP packets");
+MBUFQ_HEAD(fq_head);
 
-static int     ip_dosourceroute = 0;
-SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW,
-    &ip_dosourceroute, 0, "Enable forwarding source routed IP packets");
+static int frag_timeout_run;           /* frag timer is scheduled to run */
+static void frag_timeout(void *);
+static void frag_sched_timeout(void);
 
-static int     ip_acceptsourceroute = 0;
-SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 
-    CTLFLAG_RW, &ip_acceptsourceroute, 0, 
-    "Enable accepting source routed IP packets");
+static struct ipq *ipq_alloc(int);
+static void ipq_free(struct ipq *);
+static void ipq_updateparams(void);
+static void ip_input_second_pass(struct mbuf *, struct ifnet *,
+    u_int32_t, int, int, struct ip_fw_in_args *, int);
 
-static int     ip_keepfaith = 0;
-SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW,
-       &ip_keepfaith,  0,
-       "Enable packet capture for FAITH IPv4->IPv6 translater daemon");
+decl_lck_mtx_data(static, ipqlock);
+static lck_attr_t      *ipqlock_attr;
+static lck_grp_t       *ipqlock_grp;
+static lck_grp_attr_t  *ipqlock_grp_attr;
 
-static int     nipq = 0;       /* total # of reass queues */
-static int     maxnipq;
-SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW,
-       &maxnipq, 0,
-       "Maximum number of IPv4 fragment reassembly queue entries");
+/* Packet reassembly stuff */
+#define        IPREASS_NHASH_LOG2      6
+#define        IPREASS_NHASH           (1 << IPREASS_NHASH_LOG2)
+#define        IPREASS_HMASK           (IPREASS_NHASH - 1)
+#define        IPREASS_HASH(x, y) \
+       (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK)
 
-static int    maxfragsperpacket;
-SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW,
-       &maxfragsperpacket, 0,
+/* IP fragment reassembly queues (protected by ipqlock) */
+static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH]; /* ip reassembly queues */
+static int maxnipq;                    /* max packets in reass queues */
+static u_int32_t maxfragsperpacket;    /* max frags/packet in reass queues */
+static u_int32_t nipq;                 /* # of packets in reass queues */
+static u_int32_t ipq_limit;            /* ipq allocation limit */
+static u_int32_t ipq_count;            /* current # of allocated ipq's */
+
+static int sysctl_ipforwarding SYSCTL_HANDLER_ARGS;
+static int sysctl_maxnipq SYSCTL_HANDLER_ARGS;
+static int sysctl_maxfragsperpacket SYSCTL_HANDLER_ARGS;
+static int sysctl_reset_ip_input_stats SYSCTL_HANDLER_ARGS;
+static int sysctl_ip_input_measure_bins SYSCTL_HANDLER_ARGS;
+static int sysctl_ip_input_getperf SYSCTL_HANDLER_ARGS;
+
+int ipforwarding = 0;
+SYSCTL_PROC(_net_inet_ip, IPCTL_FORWARDING, forwarding,
+       CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, &ipforwarding, 0,
+       sysctl_ipforwarding, "I", "Enable IP forwarding between interfaces");
+
+static int ipsendredirects = 1; /* XXX */
+SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect,
+       CTLFLAG_RW | CTLFLAG_LOCKED, &ipsendredirects, 0,
+       "Enable sending IP redirects");
+
+int ip_defttl = IPDEFTTL;
+SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW | CTLFLAG_LOCKED,
+       &ip_defttl, 0, "Maximum TTL on IP packets");
+
+static int ip_dosourceroute = 0;
+SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute,
+       CTLFLAG_RW | CTLFLAG_LOCKED, &ip_dosourceroute, 0,
+       "Enable forwarding source routed IP packets");
+
+static int ip_acceptsourceroute = 0;
+SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute,
+       CTLFLAG_RW | CTLFLAG_LOCKED, &ip_acceptsourceroute, 0,
+       "Enable accepting source routed IP packets");
+
+static int ip_sendsourcequench = 0;
+SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench,
+       CTLFLAG_RW | CTLFLAG_LOCKED, &ip_sendsourcequench, 0,
+       "Enable the transmission of source quench packets");
+
+SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets,
+       CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, &maxnipq, 0, sysctl_maxnipq,
+       "I", "Maximum number of IPv4 fragment reassembly queue entries");
+
+SYSCTL_UINT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD | CTLFLAG_LOCKED,
+       &nipq, 0, "Current number of IPv4 fragment reassembly queue entries");
+
+SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragsperpacket,
+       CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, &maxfragsperpacket, 0,
+       sysctl_maxfragsperpacket, "I",
        "Maximum number of IPv4 fragments allowed per packet");
 
-static int    maxfrags;
-SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfrags, CTLFLAG_RW,
-       &maxfrags, 0, "Maximum number of IPv4 fragments allowed");
+int ip_doscopedroute = 1;
+SYSCTL_INT(_net_inet_ip, OID_AUTO, scopedroute, CTLFLAG_RD | CTLFLAG_LOCKED,
+       &ip_doscopedroute, 0, "Enable IPv4 scoped routing");
 
-static int    currentfrags = 0;
+static uint32_t ip_adj_clear_hwcksum = 0;
+SYSCTL_UINT(_net_inet_ip, OID_AUTO, adj_clear_hwcksum,
+       CTLFLAG_RW | CTLFLAG_LOCKED, &ip_adj_clear_hwcksum, 0,
+       "Invalidate hwcksum info when adjusting length");
 
 /*
  * XXX - Setting ip_checkinterface mostly implements the receive side of
@@ -189,83 +253,100 @@ static int    currentfrags = 0;
  * to the loopback interface instead of the interface where the
  * packets for those addresses are received.
  */
-static int     ip_checkinterface = 0;
-SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW,
-    &ip_checkinterface, 0, "Verify packet arrives on correct interface");
+static int ip_checkinterface = 0;
+SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW | CTLFLAG_LOCKED,
+       &ip_checkinterface, 0, "Verify packet arrives on correct interface");
+
+static int ip_chaining = 1;
+SYSCTL_INT(_net_inet_ip, OID_AUTO, rx_chaining, CTLFLAG_RW | CTLFLAG_LOCKED,
+       &ip_chaining, 1, "Do receive side ip address based chaining");
+
+static int ip_chainsz = 6;
+SYSCTL_INT(_net_inet_ip, OID_AUTO, rx_chainsz, CTLFLAG_RW | CTLFLAG_LOCKED,
+       &ip_chainsz, 1, "IP receive side max chaining");
+
+static int ip_input_measure = 0;
+SYSCTL_PROC(_net_inet_ip, OID_AUTO, input_perf,
+       CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
+       &ip_input_measure, 0, sysctl_reset_ip_input_stats, "I", "Do time measurement");
+
+static uint64_t ip_input_measure_bins = 0;
+SYSCTL_PROC(_net_inet_ip, OID_AUTO, input_perf_bins,
+       CTLTYPE_QUAD | CTLFLAG_RW | CTLFLAG_LOCKED, &ip_input_measure_bins, 0,
+       sysctl_ip_input_measure_bins, "I",
+       "bins for chaining performance data histogram");
+
+static net_perf_t net_perf;
+SYSCTL_PROC(_net_inet_ip, OID_AUTO, input_perf_data,
+       CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_LOCKED,
+       0, 0, sysctl_ip_input_getperf, "S,net_perf",
+       "IP input performance data (struct net_perf, net/net_perf.h)");
 
 #if DIAGNOSTIC
-static int     ipprintfs = 0;
+static int ipprintfs = 0;
 #endif
 
-extern struct domain inetdomain;
-extern struct protosw inetsw[];
 struct protosw *ip_protox[IPPROTO_MAX];
-static int     ipqmaxlen = IFQ_MAXLEN;
-struct in_ifaddrhead in_ifaddrhead; /* first inet address */
-struct ifqueue ipintrq;
-SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW,
-    &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue");
-SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD,
-    &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue");
 
-struct ipstat ipstat;
-SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RD,
-    &ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)");
+static lck_grp_attr_t  *in_ifaddr_rwlock_grp_attr;
+static lck_grp_t       *in_ifaddr_rwlock_grp;
+static lck_attr_t      *in_ifaddr_rwlock_attr;
+decl_lck_rw_data(, in_ifaddr_rwlock_data);
+lck_rw_t               *in_ifaddr_rwlock = &in_ifaddr_rwlock_data;
 
-/* Packet reassembly stuff */
-#define IPREASS_NHASH_LOG2      6
-#define IPREASS_NHASH           (1 << IPREASS_NHASH_LOG2)
-#define IPREASS_HMASK           (IPREASS_NHASH - 1)
-#define IPREASS_HASH(x,y) \
-       (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK)
+/* Protected by in_ifaddr_rwlock */
+struct in_ifaddrhead in_ifaddrhead;            /* first inet address */
+struct in_ifaddrhashhead *in_ifaddrhashtbl;    /* inet addr hash table  */
+
+#define        INADDR_NHASH    61
+static u_int32_t inaddr_nhash;                 /* hash table size */
+static u_int32_t inaddr_hashp;                 /* next largest prime */
 
-static struct ipq ipq[IPREASS_NHASH];
-static TAILQ_HEAD(ipq_list, ipq) ipq_list =
-       TAILQ_HEAD_INITIALIZER(ipq_list);
-const  int    ipintrq_present = 1;
-lck_mtx_t                      *ip_mutex;
-lck_attr_t             *ip_mutex_attr;
-lck_grp_t                      *ip_mutex_grp;
-lck_grp_attr_t *ip_mutex_grp_attr;
-lck_mtx_t              *inet_domain_mutex;
-extern lck_mtx_t               *domain_proto_mtx;
+static int ip_getstat SYSCTL_HANDLER_ARGS;
+struct ipstat ipstat;
+SYSCTL_PROC(_net_inet_ip, IPCTL_STATS, stats,
+       CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_LOCKED,
+       0, 0, ip_getstat, "S,ipstat",
+       "IP statistics (struct ipstat, netinet/ip_var.h)");
 
 #if IPCTL_DEFMTU
-SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW,
-    &ip_mtu, 0, "Default MTU");
-#endif
+SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW | CTLFLAG_LOCKED,
+       &ip_mtu, 0, "Default MTU");
+#endif /* IPCTL_DEFMTU */
 
 #if IPSTEALTH
 static int     ipstealth = 0;
-SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW,
-    &ipstealth, 0, "");
-#endif
-
+SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW | CTLFLAG_LOCKED,
+       &ipstealth, 0, "");
+#endif /* IPSTEALTH */
 
 /* Firewall hooks */
+#if IPFIREWALL
 ip_fw_chk_t *ip_fw_chk_ptr;
-int fw_enable = 1 ;
-int fw_one_pass = 1;
+int fw_enable = 1;
+int fw_bypass = 1;
+int fw_one_pass = 0;
+#endif /* IPFIREWALL */
 
 #if DUMMYNET
 ip_dn_io_t *ip_dn_io_ptr;
-#endif
-
-int (*fr_checkp)(struct ip *, int, struct ifnet *, int, struct mbuf **) = NULL;
+#endif /* DUMMYNET */
 
-SYSCTL_NODE(_net_inet_ip, OID_AUTO, linklocal, CTLFLAG_RW, 0, "link local");
+SYSCTL_NODE(_net_inet_ip, OID_AUTO, linklocal,
+       CTLFLAG_RW | CTLFLAG_LOCKED, 0, "link local");
 
 struct ip_linklocal_stat ip_linklocal_stat;
-SYSCTL_STRUCT(_net_inet_ip_linklocal, OID_AUTO, stat, CTLFLAG_RD,
-        &ip_linklocal_stat, ip_linklocal_stat,
-        "Number of link local packets with TTL less than 255");
+SYSCTL_STRUCT(_net_inet_ip_linklocal, OID_AUTO, stat,
+       CTLFLAG_RD | CTLFLAG_LOCKED, &ip_linklocal_stat, ip_linklocal_stat,
+       "Number of link local packets with TTL less than 255");
 
-SYSCTL_NODE(_net_inet_ip_linklocal, OID_AUTO, in, CTLFLAG_RW, 0, "link local input");
+SYSCTL_NODE(_net_inet_ip_linklocal, OID_AUTO, in,
+       CTLFLAG_RW | CTLFLAG_LOCKED, 0, "link local input");
 
 int ip_linklocal_in_allowbadttl = 1;
-SYSCTL_INT(_net_inet_ip_linklocal_in, OID_AUTO, allowbadttl, CTLFLAG_RW,
-        &ip_linklocal_in_allowbadttl, 0,
-        "Allow incoming link local packets with TTL less than 255");
+SYSCTL_INT(_net_inet_ip_linklocal_in, OID_AUTO, allowbadttl,
+       CTLFLAG_RW | CTLFLAG_LOCKED, &ip_linklocal_in_allowbadttl, 0,
+       "Allow incoming link local packets with TTL less than 255");
 
 
 /*
@@ -280,141 +361,241 @@ static  struct ip_srcrt {
        struct  in_addr dst;                    /* final destination */
        char    nop;                            /* one NOP to align */
        char    srcopt[IPOPT_OFFSET + 1];       /* OPTVAL, OLEN and OFFSET */
-       struct  in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
+       struct  in_addr route[MAX_IPOPTLEN / sizeof (struct in_addr)];
 } ip_srcrt;
 
-#ifdef __APPLE__
-extern struct mbuf*    m_dup(register struct mbuf *m, int how);
-#endif
-
-static void    save_rte(u_char *, struct in_addr);
-static int     ip_dooptions(struct mbuf *, int, struct sockaddr_in *, struct route *ipforward_rt);
-static void    ip_forward(struct mbuf *, int, struct sockaddr_in *, struct route *ipforward_rt);
-static void    ip_freef(struct ipq *);
+static void in_ifaddrhashtbl_init(void);
+static void save_rte(u_char *, struct in_addr);
+static int ip_dooptions(struct mbuf *, int, struct sockaddr_in *);
+static void ip_forward(struct mbuf *, int, struct sockaddr_in *);
+static void frag_freef(struct ipqhead *, struct ipq *);
 #if IPDIVERT
 #ifdef IPDIVERT_44
-static struct  mbuf *ip_reass(struct mbuf *,
-                       struct ipq *, struct ipq *, u_int32_t *, u_int16_t *);
-#else
-static struct  mbuf *ip_reass(struct mbuf *,
-                       struct ipq *, struct ipq *, u_int16_t *, u_int16_t *);
-#endif
-#else
-static struct  mbuf *ip_reass(struct mbuf *, struct ipq *, struct ipq *);
-#endif
-void   ipintr(void);
+static struct mbuf *ip_reass(struct mbuf *, u_int32_t *, u_int16_t *);
+#else /* !IPDIVERT_44 */
+static struct mbuf *ip_reass(struct mbuf *, u_int16_t *, u_int16_t *);
+#endif /* !IPDIVERT_44 */
+#else /* !IPDIVERT */
+static struct mbuf *ip_reass(struct mbuf *);
+#endif /* !IPDIVERT */
+static void ip_fwd_route_copyout(struct ifnet *, struct route *);
+static void ip_fwd_route_copyin(struct ifnet *, struct route *);
+static inline u_short ip_cksum(struct mbuf *, int);
+
+int ip_use_randomid = 1;
+SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW | CTLFLAG_LOCKED,
+       &ip_use_randomid, 0, "Randomize IP packets IDs");
 
-#if RANDOM_IP_ID
-extern u_short ip_id;
-#endif
+/*
+ * On platforms which require strict alignment (currently for anything but
+ * i386 or x86_64), check if the IP header pointer is 32-bit aligned; if not,
+ * copy the contents of the mbuf chain into a new chain, and free the original
+ * one.  Create some head room in the first mbuf of the new chain, in case
+ * it's needed later on.
+ */
+#if defined(__i386__) || defined(__x86_64__)
+#define        IP_HDR_ALIGNMENT_FIXUP(_m, _ifp, _action) do { } while (0)
+#else /* !__i386__ && !__x86_64__ */
+#define        IP_HDR_ALIGNMENT_FIXUP(_m, _ifp, _action) do {                  \
+       if (!IP_HDR_ALIGNED_P(mtod(_m, caddr_t))) {                     \
+               struct mbuf *_n;                                        \
+               struct ifnet *__ifp = (_ifp);                           \
+               atomic_add_64(&(__ifp)->if_alignerrs, 1);               \
+               if (((_m)->m_flags & M_PKTHDR) &&                       \
+                   (_m)->m_pkthdr.pkt_hdr != NULL)                     \
+                       (_m)->m_pkthdr.pkt_hdr = NULL;                  \
+               _n = m_defrag_offset(_m, max_linkhdr, M_NOWAIT);        \
+               if (_n == NULL) {                                       \
+                       atomic_add_32(&ipstat.ips_toosmall, 1);         \
+                       m_freem(_m);                                    \
+                       (_m) = NULL;                                    \
+                       _action;                                        \
+               } else {                                                \
+                       VERIFY(_n != (_m));                             \
+                       (_m) = _n;                                      \
+               }                                                       \
+       }                                                               \
+} while (0)
+#endif /* !__i386__ && !__x86_64__ */
 
-extern u_long  route_generation;
-extern int apple_hwcksum_rx;
+/*
+ * GRE input handler function, settable via ip_gre_register_input() for PPTP.
+ */
+static gre_input_func_t gre_input_func;
 
 /*
  * IP initialization: fill in IP protocol switch table.
  * All protocols not implemented in kernel go to raw IP protocol handler.
  */
 void
-ip_init()
+ip_init(struct protosw *pp, struct domain *dp)
 {
-       register struct protosw *pr;
-       register int i;
-       static ip_initialized = 0;
-       struct timeval timenow;
-
-
-       if (!ip_initialized)
-       {
-               TAILQ_INIT(&in_ifaddrhead);
-               pr = pffindproto_locked(PF_INET, IPPROTO_RAW, SOCK_RAW);
-               if (pr == 0)
-                       panic("ip_init");
-               for (i = 0; i < IPPROTO_MAX; i++)
-                       ip_protox[i] = pr;
-               for (pr = inetdomain.dom_protosw; pr; pr = pr->pr_next)
-               {       if(!((unsigned int)pr->pr_domain)) continue;    /* If uninitialized, skip */
-                       if (pr->pr_domain->dom_family == PF_INET &&
-                           pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
+       static int ip_initialized = 0;
+       struct protosw *pr;
+       struct timeval tv;
+       int i;
+
+       domain_proto_mtx_lock_assert_held();
+       VERIFY((pp->pr_flags & (PR_INITIALIZED|PR_ATTACHED)) == PR_ATTACHED);
+
+       /* ipq_alloc() uses mbufs for IP fragment queue structures */
+       _CASSERT(sizeof (struct ipq) <= _MLEN);
+
+       /*
+        * Some ioctls (e.g. SIOCAIFADDR) use ifaliasreq struct, which is
+        * interchangeable with in_aliasreq; they must have the same size.
+        */
+       _CASSERT(sizeof (struct ifaliasreq) == sizeof (struct in_aliasreq));
+
+       if (ip_initialized)
+               return;
+       ip_initialized = 1;
+
+       PE_parse_boot_argn("net.inet.ip.scopedroute",
+           &ip_doscopedroute, sizeof (ip_doscopedroute));
+
+       in_ifaddr_init();
+
+       in_ifaddr_rwlock_grp_attr = lck_grp_attr_alloc_init();
+       in_ifaddr_rwlock_grp = lck_grp_alloc_init("in_ifaddr_rwlock",
+           in_ifaddr_rwlock_grp_attr);
+       in_ifaddr_rwlock_attr = lck_attr_alloc_init();
+       lck_rw_init(in_ifaddr_rwlock, in_ifaddr_rwlock_grp,
+           in_ifaddr_rwlock_attr);
+
+       TAILQ_INIT(&in_ifaddrhead);
+       in_ifaddrhashtbl_init();
+
+       ip_moptions_init();
+
+       pr = pffindproto_locked(PF_INET, IPPROTO_RAW, SOCK_RAW);
+       if (pr == NULL) {
+               panic("%s: Unable to find [PF_INET,IPPROTO_RAW,SOCK_RAW]\n",
+                   __func__);
+               /* NOTREACHED */
+       }
+
+       /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */
+       for (i = 0; i < IPPROTO_MAX; i++)
+               ip_protox[i] = pr;
+       /*
+        * Cycle through IP protocols and put them into the appropriate place
+        * in ip_protox[], skipping protocols IPPROTO_{IP,RAW}.
+        */
+       VERIFY(dp == inetdomain && dp->dom_family == PF_INET);
+       TAILQ_FOREACH(pr, &dp->dom_protosw, pr_entry) {
+               VERIFY(pr->pr_domain == dp);
+               if (pr->pr_protocol != 0 && pr->pr_protocol != IPPROTO_RAW) {
+                       /* Be careful to only index valid IP protocols. */
+                       if (pr->pr_protocol < IPPROTO_MAX)
                                ip_protox[pr->pr_protocol] = pr;
                }
-               for (i = 0; i < IPREASS_NHASH; i++)
-                   ipq[i].next = ipq[i].prev = &ipq[i];
+       }
+
+       /* IP fragment reassembly queue lock */
+       ipqlock_grp_attr  = lck_grp_attr_alloc_init();
+       ipqlock_grp = lck_grp_alloc_init("ipqlock", ipqlock_grp_attr);
+       ipqlock_attr = lck_attr_alloc_init();
+       lck_mtx_init(&ipqlock, ipqlock_grp, ipqlock_attr);
+
+       lck_mtx_lock(&ipqlock);
+       /* Initialize IP reassembly queue. */
+       for (i = 0; i < IPREASS_NHASH; i++)
+               TAILQ_INIT(&ipq[i]);
 
        maxnipq = nmbclusters / 32;
-       maxfrags = maxnipq * 2;
        maxfragsperpacket = 128; /* enough for 64k in 512 byte fragments */
+       ipq_updateparams();
+       lck_mtx_unlock(&ipqlock);
+
+       getmicrotime(&tv);
+       ip_id = RandomULong() ^ tv.tv_usec;
+       ip_initid();
+
+       ipf_init();
+
+#if IPSEC
+       sadb_stat_mutex_grp_attr = lck_grp_attr_alloc_init();
+       sadb_stat_mutex_grp = lck_grp_alloc_init("sadb_stat",
+           sadb_stat_mutex_grp_attr);
+       sadb_stat_mutex_attr = lck_attr_alloc_init();
+       lck_mtx_init(sadb_stat_mutex, sadb_stat_mutex_grp,
+           sadb_stat_mutex_attr);
 
-#if RANDOM_IP_ID
-               getmicrouptime(&timenow);
-               ip_id = timenow.tv_sec & 0xffff;
 #endif
-               ipintrq.ifq_maxlen = ipqmaxlen;
+       arp_init();
+}
 
-               ipf_init();
+/*
+ * Initialize IPv4 source address hash table.
+ */
+static void
+in_ifaddrhashtbl_init(void)
+{
+       int i, k, p;
 
-               ip_mutex_grp_attr  = lck_grp_attr_alloc_init();
+       if (in_ifaddrhashtbl != NULL)
+               return;
 
-               ip_mutex_grp = lck_grp_alloc_init("ip", ip_mutex_grp_attr);
+       PE_parse_boot_argn("inaddr_nhash", &inaddr_nhash,
+           sizeof (inaddr_nhash));
+       if (inaddr_nhash == 0)
+               inaddr_nhash = INADDR_NHASH;
 
-               ip_mutex_attr = lck_attr_alloc_init();
+       MALLOC(in_ifaddrhashtbl, struct in_ifaddrhashhead *,
+           inaddr_nhash * sizeof (*in_ifaddrhashtbl),
+           M_IFADDR, M_WAITOK | M_ZERO);
+       if (in_ifaddrhashtbl == NULL)
+               panic("in_ifaddrhashtbl_init allocation failed");
 
-               if ((ip_mutex = lck_mtx_alloc_init(ip_mutex_grp, ip_mutex_attr)) == NULL) {
-                       printf("ip_init: can't alloc ip_mutex\n");
-                       return;
+       /*
+        * Generate the next largest prime greater than inaddr_nhash.
+        */
+       k = (inaddr_nhash % 2 == 0) ? inaddr_nhash + 1 : inaddr_nhash + 2;
+       for (;;) {
+               p = 1;
+               for (i = 3; i * i <= k; i += 2) {
+                       if (k % i == 0)
+                               p = 0;
                }
-
-               ip_initialized = 1;
+               if (p == 1)
+                       break;
+               k += 2;
        }
+       inaddr_hashp = k;
 }
 
-static void
-ip_proto_input(
-       protocol_family_t       protocol,
-       mbuf_t                          packet)
+u_int32_t
+inaddr_hashval(u_int32_t key)
 {
-       ip_input(packet);
+       /*
+        * The hash index is the computed prime times the key modulo
+        * the hash size, as documented in "Introduction to Algorithms"
+        * (Cormen, Leiserson, Rivest).
+        */
+       if (inaddr_nhash > 1)
+               return ((key * inaddr_hashp) % inaddr_nhash);
+       else
+               return (0);
 }
 
-/* Initialize the PF_INET domain, and add in the pre-defined protos */
 void
-in_dinit()
-{      register int i;
-       register struct protosw *pr;
-       register struct domain *dp;
-       static inetdomain_initted = 0;
-       extern int in_proto_count; 
-
-       if (!inetdomain_initted)
-       {
-               kprintf("Initing %d protosw entries\n", in_proto_count);
-               dp = &inetdomain;
-               dp->dom_flags = DOM_REENTRANT;
-
-               for (i=0, pr = &inetsw[0]; i<in_proto_count; i++, pr++)
-                       net_add_proto(pr, dp);
-               inet_domain_mutex = dp->dom_mtx;
-               inetdomain_initted = 1;
-       
-               lck_mtx_unlock(domain_proto_mtx);       
-               proto_register_input(PF_INET, ip_proto_input, NULL);
-               lck_mtx_lock(domain_proto_mtx); 
-       }
+ip_proto_dispatch_in_wrapper(struct mbuf *m, int hlen, u_int8_t proto)
+{
+       ip_proto_dispatch_in(m, hlen, proto, 0);
 }
 
 __private_extern__ void
-ip_proto_dispatch_in(
-                                       struct mbuf     *m,
-                                       int                     hlen,
-                                       u_int8_t        proto,
-                                       ipfilter_t      inject_ipfref)
+ip_proto_dispatch_in(struct mbuf *m, int hlen, u_int8_t proto,
+    ipfilter_t inject_ipfref)
 {
        struct ipfilter *filter;
-       int seen = (inject_ipfref == 0);
+       int seen = (inject_ipfref == NULL);
        int     changed_header = 0;
        struct ip *ip;
+       void (*pr_input)(struct mbuf *, int len);
 
-       if (!TAILQ_EMPTY(&ipv4_filters)) {      
+       if (!TAILQ_EMPTY(&ipv4_filters)) {
                ipf_ref();
                TAILQ_FOREACH(filter, &ipv4_filters, ipf_link) {
                        if (seen == 0) {
@@ -422,17 +603,30 @@ ip_proto_dispatch_in(
                                        seen = 1;
                        } else if (filter->ipf_filter.ipf_input) {
                                errno_t result;
-               
+
                                if (changed_header == 0) {
+                                       /*
+                                        * Perform IP header alignment fixup,
+                                        * if needed, before passing packet
+                                        * into filter(s).
+                                        */
+                                       IP_HDR_ALIGNMENT_FIXUP(m,
+                                           m->m_pkthdr.rcvif, ipf_unref());
+
+                                       /* ipf_unref() already called */
+                                       if (m == NULL)
+                                               return;
+
                                        changed_header = 1;
                                        ip = mtod(m, struct ip *);
                                        ip->ip_len = htons(ip->ip_len + hlen);
                                        ip->ip_off = htons(ip->ip_off);
                                        ip->ip_sum = 0;
-                                       ip->ip_sum = in_cksum(m, hlen);
+                                       ip->ip_sum = ip_cksum_hdr_in(m, hlen);
                                }
                                result = filter->ipf_filter.ipf_input(
-                                       filter->ipf_filter.cookie, (mbuf_t*)&m, hlen, proto);
+                                   filter->ipf_filter.cookie, (mbuf_t *)&m,
+                                   hlen, proto);
                                if (result == EJUSTRETURN) {
                                        ipf_unref();
                                        return;
@@ -442,201 +636,458 @@ ip_proto_dispatch_in(
                                        m_freem(m);
                                        return;
                                }
-       }
+                       }
                }
                ipf_unref();
        }
+
+       /* Perform IP header alignment fixup (post-filters), if needed */
+       IP_HDR_ALIGNMENT_FIXUP(m, m->m_pkthdr.rcvif, return);
+
        /*
         * If there isn't a specific lock for the protocol
         * we're about to call, use the generic lock for AF_INET.
         * otherwise let the protocol deal with its own locking
         */
        ip = mtod(m, struct ip *);
-       
+
        if (changed_header) {
                ip->ip_len = ntohs(ip->ip_len) - hlen;
                ip->ip_off = ntohs(ip->ip_off);
        }
-       
-       if (!(ip_protox[ip->ip_p]->pr_flags & PR_PROTOLOCK)) {
+
+       if ((pr_input = ip_protox[ip->ip_p]->pr_input) == NULL) {
+               m_freem(m);
+       } else if (!(ip_protox[ip->ip_p]->pr_flags & PR_PROTOLOCK)) {
                lck_mtx_lock(inet_domain_mutex);
-               (*ip_protox[ip->ip_p]->pr_input)(m, hlen);
+               pr_input(m, hlen);
                lck_mtx_unlock(inet_domain_mutex);
-       }       
-       else     
-               (*ip_protox[ip->ip_p]->pr_input)(m, hlen);
-               
+       } else {
+               pr_input(m, hlen);
+       }
 }
 
-/* 
- * ipforward_rt cleared in in_addroute()
- * when a new route is successfully created.
- */
-static struct  sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
+struct pktchain_elm {
+       struct mbuf     *pkte_head;
+       struct mbuf     *pkte_tail;
+       struct in_addr  pkte_saddr;
+       struct in_addr  pkte_daddr;
+       uint16_t        pkte_npkts;
+       uint16_t        pkte_proto;
+       uint32_t        pkte_nbytes;
+};
+
+typedef struct pktchain_elm pktchain_elm_t;
+
+/* Store upto PKTTBL_SZ unique flows on the stack */
+#define PKTTBL_SZ      7
+
+static struct mbuf *
+ip_chain_insert(struct mbuf *packet, pktchain_elm_t *tbl)
+{
+       struct ip*      ip;
+       int             pkttbl_idx = 0;
+
+       ip = mtod(packet, struct ip*);
+
+       /* reusing the hash function from inaddr_hashval */
+       pkttbl_idx = inaddr_hashval(ntohs(ip->ip_src.s_addr)) % PKTTBL_SZ;
+       if (tbl[pkttbl_idx].pkte_head == NULL) {
+               tbl[pkttbl_idx].pkte_head = packet;
+               tbl[pkttbl_idx].pkte_saddr.s_addr = ip->ip_src.s_addr;
+               tbl[pkttbl_idx].pkte_daddr.s_addr = ip->ip_dst.s_addr;
+               tbl[pkttbl_idx].pkte_proto = ip->ip_p;
+       } else {
+               if ((ip->ip_dst.s_addr == tbl[pkttbl_idx].pkte_daddr.s_addr) &&
+                   (ip->ip_src.s_addr == tbl[pkttbl_idx].pkte_saddr.s_addr) &&
+                   (ip->ip_p == tbl[pkttbl_idx].pkte_proto)) {
+               } else {
+                       return (packet);
+               }
+       }
+       if (tbl[pkttbl_idx].pkte_tail != NULL)
+               mbuf_setnextpkt(tbl[pkttbl_idx].pkte_tail, packet);
+
+       tbl[pkttbl_idx].pkte_tail = packet;
+       tbl[pkttbl_idx].pkte_npkts += 1;
+       tbl[pkttbl_idx].pkte_nbytes += packet->m_pkthdr.len;
+       return (NULL);
+}
+
+/* args is a dummy variable here for backward compatibility */
+static void
+ip_input_second_pass_loop_tbl(pktchain_elm_t *tbl, struct ip_fw_in_args *args)
+{
+       int i = 0;
+
+       for (i = 0; i < PKTTBL_SZ; i++) {
+               if (tbl[i].pkte_head != NULL) {
+                       struct mbuf *m = tbl[i].pkte_head;
+                       ip_input_second_pass(m, m->m_pkthdr.rcvif, 0,
+                           tbl[i].pkte_npkts, tbl[i].pkte_nbytes, args, 0);
+
+                       if (tbl[i].pkte_npkts > 2)
+                               ipstat.ips_rxc_chainsz_gt2++;
+                       if (tbl[i].pkte_npkts > 4)
+                               ipstat.ips_rxc_chainsz_gt4++;
+
+                       if (ip_input_measure)
+                               net_perf_histogram(&net_perf, tbl[i].pkte_npkts);
+
+                       tbl[i].pkte_head = tbl[i].pkte_tail = NULL;
+                       tbl[i].pkte_npkts = 0;
+                       tbl[i].pkte_nbytes = 0;
+                       /* no need to initialize address and protocol in tbl */
+               }
+       }
+}
+
+static void
+ip_input_cpout_args(struct ip_fw_in_args *args, struct ip_fw_args *args1,
+    boolean_t *done_init)
+{
+       if (*done_init == FALSE) {
+               bzero(args1, sizeof(struct ip_fw_args));
+               *done_init = TRUE;
+       }
+       args1->fwa_next_hop = args->fwai_next_hop;
+       args1->fwa_ipfw_rule = args->fwai_ipfw_rule;
+       args1->fwa_pf_rule = args->fwai_pf_rule;
+       args1->fwa_divert_rule = args->fwai_divert_rule;
+}
+
+static void
+ip_input_cpin_args(struct ip_fw_args *args1, struct ip_fw_in_args *args)
+{
+       args->fwai_next_hop = args1->fwa_next_hop;
+       args->fwai_ipfw_rule = args1->fwa_ipfw_rule;
+       args->fwai_pf_rule = args1->fwa_pf_rule;
+       args->fwai_divert_rule = args1->fwa_divert_rule;
+}
+
+typedef enum {
+       IPINPUT_DOCHAIN = 0,
+       IPINPUT_DONTCHAIN,
+       IPINPUT_FREED,
+       IPINPUT_DONE
+} ipinput_chain_ret_t;
+
+static void
+ip_input_update_nstat(struct ifnet *ifp, struct in_addr src_ip,
+    u_int32_t packets, u_int32_t bytes)
+{
+       if (nstat_collect) {
+               struct rtentry *rt = ifnet_cached_rtlookup_inet(ifp,
+                   src_ip);
+               if (rt != NULL) {
+                       nstat_route_rx(rt, packets, bytes, 0);
+                       rtfree(rt);
+               }
+       }
+}
+
+static void
+ip_input_dispatch_chain(struct mbuf *m)
+{
+       struct mbuf *tmp_mbuf = m;
+       struct mbuf *nxt_mbuf = NULL;
+       struct ip *ip = NULL;
+       unsigned int hlen;
+
+       ip = mtod(tmp_mbuf, struct ip *);
+       hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+       while(tmp_mbuf) {
+               nxt_mbuf = mbuf_nextpkt(tmp_mbuf);
+               mbuf_setnextpkt(tmp_mbuf, NULL);
+
+               if ((sw_lro) && (ip->ip_p == IPPROTO_TCP))
+                       tmp_mbuf = tcp_lro(tmp_mbuf, hlen);
+               if (tmp_mbuf)
+                       ip_proto_dispatch_in(tmp_mbuf, hlen, ip->ip_p, 0);
+               tmp_mbuf = nxt_mbuf;
+               if (tmp_mbuf) {
+                       ip = mtod(tmp_mbuf, struct ip *);
+                       /* first mbuf of chain already has adjusted ip_len */
+                       hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+                       ip->ip_len -= hlen;
+               }
+       }
+}
+
+static void
+ip_input_setdst_chain(struct mbuf *m, uint32_t ifindex, struct in_ifaddr *ia)
+{
+       struct mbuf *tmp_mbuf = m;
+
+       while (tmp_mbuf) {
+               ip_setdstifaddr_info(tmp_mbuf, ifindex, ia);
+               tmp_mbuf = mbuf_nextpkt(tmp_mbuf);
+       }
+}
 
 /*
- * Ip input routine.  Checksum and byte swap header.  If fragmented
- * try to reassemble.  Process options.  Pass to next level.
+ * First pass does all essential packet validation and places on a per flow
+ * queue for doing operations that have same outcome for all packets of a flow.
+ * div_info is packet divert/tee info
  */
-void
-ip_input(struct mbuf *m)
+static ipinput_chain_ret_t
+ip_input_first_pass(struct mbuf *m, u_int32_t *div_info,
+    struct ip_fw_in_args *args, int *ours, struct mbuf **modm)
 {
-       struct ip *ip;
-       struct ipq *fp;
-       struct in_ifaddr *ia = NULL;
-       int    i, hlen, mff, checkif;
-       u_short sum;
-       struct in_addr pkt_dst;
-       u_int32_t div_info = 0;         /* packet divert/tee info */
-       struct ip_fw_args args;
-       ipfilter_t inject_filter_ref = 0;
-       struct m_tag    *tag;
-       struct route    ipforward_rt = { 0 };
-       
-       lck_mtx_lock(ip_mutex);
+       struct ip       *ip;
+       struct ifnet    *inifp;
+       unsigned int    hlen;
+       int             retval = IPINPUT_DOCHAIN;
+       int             len = 0;
+       struct in_addr  src_ip;
+#if IPFIREWALL
+       int             i;
+#endif
+#if IPFIREWALL || DUMMYNET
+       struct m_tag            *copy;
+       struct m_tag            *p;
+       boolean_t               delete = FALSE;
+       struct ip_fw_args       args1;
+       boolean_t               init = FALSE;
+#endif
+       ipfilter_t inject_filter_ref = NULL;
+
+#if !IPFIREWALL
+#pragma unused (args)
+#endif
+
+#if !IPDIVERT
+#pragma unused (div_info)
+#pragma unused (ours)
+#endif
 
-       args.eh = NULL;
-       args.oif = NULL;
-       args.rule = NULL;
-       args.divert_rule = 0;                   /* divert cookie */
-       args.next_hop = NULL;
+#if !IPFIREWALL_FORWARD
+#pragma unused (ours)
+#endif
+
+       /* Check if the mbuf is still valid after interface filter processing */
+       MBUF_INPUT_CHECK(m, m->m_pkthdr.rcvif);
+       inifp = mbuf_pkthdr_rcvif(m);
+       VERIFY(inifp != NULL);
+
+       /* Perform IP header alignment fixup, if needed */
+       IP_HDR_ALIGNMENT_FIXUP(m, inifp, goto bad);
+
+       m->m_pkthdr.pkt_flags &= ~PKTF_FORWARDED;
+
+#if IPFIREWALL || DUMMYNET
+
+       /*
+        * Don't bother searching for tag(s) if there's none.
+        */
+       if (SLIST_EMPTY(&m->m_pkthdr.tags))
+               goto ipfw_tags_done;
 
        /* Grab info from mtags prepended to the chain */
+       p = m_tag_first(m);
+       while (p) {
+               if (p->m_tag_id == KERNEL_MODULE_TAG_ID) {
 #if DUMMYNET
-       if ((tag = m_tag_locate(m, KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_DUMMYNET, NULL)) != NULL) {
-               struct dn_pkt_tag       *dn_tag;
-               
-               dn_tag = (struct dn_pkt_tag *)(tag+1);
-               args.rule = dn_tag->rule;
-               
-               m_tag_delete(m, tag);
-       }
-#endif /* DUMMYNET */
+                       if (p->m_tag_type == KERNEL_TAG_TYPE_DUMMYNET) {
+                               struct dn_pkt_tag *dn_tag;
 
-       if ((tag = m_tag_locate(m, KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_DIVERT, NULL)) != NULL) {
-               struct divert_tag       *div_tag;
-               
-               div_tag = (struct divert_tag *)(tag+1);
-               args.divert_rule = div_tag->cookie;
+                               dn_tag = (struct dn_pkt_tag *)(p+1);
+                               args->fwai_ipfw_rule = dn_tag->dn_ipfw_rule;
+                               args->fwai_pf_rule = dn_tag->dn_pf_rule;
+                               delete = TRUE;
+                       }
+#endif
 
-               m_tag_delete(m, tag);
-       }
-       if ((tag = m_tag_locate(m, KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_IPFORWARD, NULL)) != NULL) {
-               struct ip_fwd_tag       *ipfwd_tag;
-               
-               ipfwd_tag = (struct ip_fwd_tag *)(tag+1);
-               args.next_hop = ipfwd_tag->next_hop;
+#if IPDIVERT
+                       if (p->m_tag_type == KERNEL_TAG_TYPE_DIVERT) {
+                               struct divert_tag *div_tag;
 
-               m_tag_delete(m, tag);
+                               div_tag = (struct divert_tag *)(p+1);
+                               args->fwai_divert_rule = div_tag->cookie;
+                               delete = TRUE;
+                       }
+#endif
+
+                       if (p->m_tag_type == KERNEL_TAG_TYPE_IPFORWARD) {
+                               struct ip_fwd_tag *ipfwd_tag;
+
+                               ipfwd_tag = (struct ip_fwd_tag *)(p+1);
+                               args->fwai_next_hop = ipfwd_tag->next_hop;
+                               delete = TRUE;
+                       }
+
+                       if (delete) {
+                               copy = p;
+                               p = m_tag_next(m, p);
+                               m_tag_delete(m, copy);
+                       } else  {
+                               p = m_tag_next(m, p);
+                       }
+               } else {
+                       p = m_tag_next(m, p);
+               }
        }
-       
-#if    DIAGNOSTIC
-       if (m == NULL || (m->m_flags & M_PKTHDR) == 0)
+
+#if DIAGNOSTIC
+       if (m == NULL || !(m->m_flags & M_PKTHDR))
                panic("ip_input no HDR");
 #endif
 
-       if (args.rule) {        /* dummynet already filtered us */
-            ip = mtod(m, struct ip *);
-            hlen = IP_VHL_HL(ip->ip_vhl) << 2;
-            inject_filter_ref = ipf_get_inject_filter(m);
-            goto iphack ;
+#if DUMMYNET
+       if (args->fwai_ipfw_rule || args->fwai_pf_rule) {
+               /* dummynet already filtered us */
+               ip = mtod(m, struct ip *);
+               hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+               inject_filter_ref = ipf_get_inject_filter(m);
+#if IPFIREWALL
+               if (args->fwai_ipfw_rule)
+                       goto iphack;
+#endif /* IPFIREWALL */
+               if (args->fwai_pf_rule)
+                       goto check_with_pf;
        }
-       
+#endif /* DUMMYNET */
+ipfw_tags_done:
+#endif /* IPFIREWALL || DUMMYNET */
+
        /*
-        * No need to proccess packet twice if we've 
-        * already seen it
+        * No need to process packet twice if we've already seen it.
         */
-       inject_filter_ref = ipf_get_inject_filter(m);
-       if (inject_filter_ref != 0) {
-               lck_mtx_unlock(ip_mutex);
+       if (!SLIST_EMPTY(&m->m_pkthdr.tags))
+               inject_filter_ref = ipf_get_inject_filter(m);
+       if (inject_filter_ref != NULL) {
                ip = mtod(m, struct ip *);
                hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+
+               DTRACE_IP6(receive, struct mbuf *, m, struct inpcb *, NULL,
+                   struct ip *, ip, struct ifnet *, inifp,
+                   struct ip *, ip, struct ip6_hdr *, NULL);
+
                ip->ip_len = ntohs(ip->ip_len) - hlen;
                ip->ip_off = ntohs(ip->ip_off);
                ip_proto_dispatch_in(m, hlen, ip->ip_p, inject_filter_ref);
-               return;
+               return (IPINPUT_DONE);
        }
 
-       ipstat.ips_total++;
-
-       if (m->m_pkthdr.len < sizeof(struct ip))
-               goto tooshort;
+       if (m->m_pkthdr.len < sizeof (struct ip)) {
+               OSAddAtomic(1, &ipstat.ips_total);
+               OSAddAtomic(1, &ipstat.ips_tooshort);
+               m_freem(m);
+               return (IPINPUT_FREED);
+       }
 
        if (m->m_len < sizeof (struct ip) &&
-           (m = m_pullup(m, sizeof (struct ip))) == 0) {
-               ipstat.ips_toosmall++;
-               lck_mtx_unlock(ip_mutex);
-               return;
+           (m = m_pullup(m, sizeof (struct ip))) == NULL) {
+               OSAddAtomic(1, &ipstat.ips_total);
+               OSAddAtomic(1, &ipstat.ips_toosmall);
+               return (IPINPUT_FREED);
        }
+
        ip = mtod(m, struct ip *);
+       *modm = m;
 
-       KERNEL_DEBUG(DBG_LAYER_BEG, ip->ip_dst.s_addr, 
-                    ip->ip_src.s_addr, ip->ip_p, ip->ip_off, ip->ip_len);
+       KERNEL_DEBUG(DBG_LAYER_BEG, ip->ip_dst.s_addr, ip->ip_src.s_addr,
+           ip->ip_p, ip->ip_off, ip->ip_len);
 
        if (IP_VHL_V(ip->ip_vhl) != IPVERSION) {
-               ipstat.ips_badvers++;
-               goto bad;
+               OSAddAtomic(1, &ipstat.ips_total);
+               OSAddAtomic(1, &ipstat.ips_badvers);
+               KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
+               m_freem(m);
+               return (IPINPUT_FREED);
        }
 
        hlen = IP_VHL_HL(ip->ip_vhl) << 2;
-       if (hlen < sizeof(struct ip)) { /* minimum header length */
-               ipstat.ips_badhlen++;
-               goto bad;
+       if (hlen < sizeof (struct ip)) {
+               OSAddAtomic(1, &ipstat.ips_total);
+               OSAddAtomic(1, &ipstat.ips_badhlen);
+               KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
+               m_freem(m);
+               return (IPINPUT_FREED);
        }
+
        if (hlen > m->m_len) {
-               if ((m = m_pullup(m, hlen)) == 0) {
-                       ipstat.ips_badhlen++;
-                       lck_mtx_unlock(ip_mutex);
-                       return;
+               if ((m = m_pullup(m, hlen)) == NULL) {
+                       OSAddAtomic(1, &ipstat.ips_total);
+                       OSAddAtomic(1, &ipstat.ips_badhlen);
+                       KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
+                       return (IPINPUT_FREED);
                }
                ip = mtod(m, struct ip *);
+               *modm = m;
        }
 
        /* 127/8 must not appear on wire - RFC1122 */
        if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
            (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
-               if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
-                       ipstat.ips_badaddr++;
-                       goto bad;
+               /*
+                * Allow for the following exceptions:
+                *
+                *   1. If the packet was sent to loopback (i.e. rcvif
+                *      would have been set earlier at output time.)
+                *
+                *   2. If the packet was sent out on loopback from a local
+                *      source address which belongs to a non-loopback
+                *      interface (i.e. rcvif may not necessarily be a
+                *      loopback interface, hence the test for PKTF_LOOP.)
+                *      Unlike IPv6, there is no interface scope ID, and
+                *      therefore we don't care so much about PKTF_IFINFO.
+                */
+               if (!(inifp->if_flags & IFF_LOOPBACK) &&
+                    !(m->m_pkthdr.pkt_flags & PKTF_LOOP)) {
+                       OSAddAtomic(1, &ipstat.ips_total);
+                       OSAddAtomic(1, &ipstat.ips_badaddr);
+                       KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
+                       m_freem(m);
+                       return (IPINPUT_FREED);
                }
        }
 
-       /* IPv4 Link-Local Addresses as defined in <draft-ietf-zeroconf-ipv4-linklocal-05.txt> */
-       if ((IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr)) || 
+       /* IPv4 Link-Local Addresses as defined in RFC3927 */
+       if ((IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr)) ||
            IN_LINKLOCAL(ntohl(ip->ip_src.s_addr)))) {
                ip_linklocal_stat.iplls_in_total++;
                if (ip->ip_ttl != MAXTTL) {
-                       ip_linklocal_stat.iplls_in_badttl++;
+                       OSAddAtomic(1, &ip_linklocal_stat.iplls_in_badttl);
                        /* Silently drop link local traffic with bad TTL */
-                       if (!ip_linklocal_in_allowbadttl)
-                               goto bad;
+                       if (!ip_linklocal_in_allowbadttl) {
+                               OSAddAtomic(1, &ipstat.ips_total);
+                               KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
+                               m_freem(m);
+                               return (IPINPUT_FREED);
+                       }
                }
        }
-       if ((IF_HWASSIST_CSUM_FLAGS(m->m_pkthdr.rcvif->if_hwassist) == 0) 
-           || (apple_hwcksum_rx == 0) ||
-          ((m->m_pkthdr.csum_flags & CSUM_TCP_SUM16) && ip->ip_p != IPPROTO_TCP)) {
-                       m->m_pkthdr.csum_flags = 0; /* invalidate HW generated checksum flags */
-       }
 
-       if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
-               sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
-       } else {
-               sum = in_cksum(m, hlen);
-       }
-       if (sum) {
-               ipstat.ips_badsum++;
-               goto bad;
+       if (ip_cksum(m, hlen)) {
+               OSAddAtomic(1, &ipstat.ips_total);
+               KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
+               m_freem(m);
+               return (IPINPUT_FREED);
        }
 
+       DTRACE_IP6(receive, struct mbuf *, m, struct inpcb *, NULL,
+           struct ip *, ip, struct ifnet *, inifp,
+           struct ip *, ip, struct ip6_hdr *, NULL);
+
        /*
         * Convert fields to host representation.
         */
+#if BYTE_ORDER != BIG_ENDIAN
        NTOHS(ip->ip_len);
+#endif
+
        if (ip->ip_len < hlen) {
-               ipstat.ips_badlen++;
-               goto bad;
+               OSAddAtomic(1, &ipstat.ips_total);
+               OSAddAtomic(1, &ipstat.ips_badlen);
+               KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
+               m_freem(m);
+               return (IPINPUT_FREED);
        }
+
+#if BYTE_ORDER != BIG_ENDIAN
        NTOHS(ip->ip_off);
+#endif
 
        /*
         * Check that the amount of data in the buffers
@@ -645,99 +1096,1000 @@ ip_input(struct mbuf *m)
         * Drop packet if shorter than we expect.
         */
        if (m->m_pkthdr.len < ip->ip_len) {
-tooshort:
-               ipstat.ips_tooshort++;
-               goto bad;
+               OSAddAtomic(1, &ipstat.ips_total);
+               OSAddAtomic(1, &ipstat.ips_tooshort);
+               KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
+               m_freem(m);
+               return (IPINPUT_FREED);
        }
-       if (m->m_pkthdr.len > ip->ip_len) {
-               /* Invalidate hwcksuming */
-               m->m_pkthdr.csum_flags = 0;
-               m->m_pkthdr.csum_data = 0;
 
-               if (m->m_len == m->m_pkthdr.len) {
+       if (m->m_pkthdr.len > ip->ip_len) {
+               /*
+                * Invalidate hardware checksum info if ip_adj_clear_hwcksum
+                * is set; useful to handle buggy drivers.  Note that this
+                * should not be enabled by default, as we may get here due
+                * to link-layer padding.
+                */
+               if (ip_adj_clear_hwcksum &&
+                   (m->m_pkthdr.csum_flags & CSUM_DATA_VALID) &&
+                   !(inifp->if_flags & IFF_LOOPBACK) &&
+                   !(m->m_pkthdr.pkt_flags & PKTF_LOOP)) {
+                       m->m_pkthdr.csum_flags &= ~CSUM_DATA_VALID;
+                       m->m_pkthdr.csum_data = 0;
+                       ipstat.ips_adj_hwcsum_clr++;
+               }
+
+               ipstat.ips_adj++;
+               if (m->m_len == m->m_pkthdr.len) {
                        m->m_len = ip->ip_len;
                        m->m_pkthdr.len = ip->ip_len;
                } else
                        m_adj(m, ip->ip_len - m->m_pkthdr.len);
        }
 
+       /* for consistency */
+       m->m_pkthdr.pkt_proto = ip->ip_p;
+
+       /* for netstat route statistics */
+       src_ip = ip->ip_src;
+       len = m->m_pkthdr.len;
+
+#if DUMMYNET
+check_with_pf:
+#endif
+#if PF
+       /* Invoke inbound packet filter */
+       if (PF_IS_ENABLED) {
+               int error;
+               ip_input_cpout_args(args, &args1, &init);
+
+#if DUMMYNET
+               error = pf_af_hook(inifp, NULL, &m, AF_INET, TRUE, &args1);
+#else
+               error = pf_af_hook(inifp, NULL, &m, AF_INET, TRUE, NULL);
+#endif /* DUMMYNET */
+               if (error != 0 || m == NULL) {
+                       if (m != NULL) {
+                               panic("%s: unexpected packet %p\n",
+                                   __func__, m);
+                               /* NOTREACHED */
+                       }
+                       /* Already freed by callee */
+                       ip_input_update_nstat(inifp, src_ip, 1, len);
+                       KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
+                       OSAddAtomic(1, &ipstat.ips_total);
+                       return (IPINPUT_FREED);
+               }
+               ip = mtod(m, struct ip *);
+               hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+               *modm = m;
+               ip_input_cpin_args(&args1, args);
+       }
+#endif /* PF */
+
 #if IPSEC
-       if (ipsec_bypass == 0 && ipsec_gethist(m, NULL))
+       if (ipsec_bypass == 0 && ipsec_gethist(m, NULL)) {
+               retval = IPINPUT_DONTCHAIN; /* XXX scope for chaining here? */
                goto pass;
+       }
 #endif
 
-       /*
-        * IpHack's section.
-        * Right now when no processing on packet has done
-        * and it is still fresh out of network we do our black
-        * deals with it.
-        * - Firewall: deny/allow/divert
-        * - Xlate: translate packet's addr/port (NAT).
-        * - Pipe: pass pkt through dummynet.
-        * - Wrap: fake packet's addr/port <unimpl.>
-        * - Encapsulate: put it in another IP and send out. <unimp.>
-        */
-
-#if defined(IPFIREWALL) && defined(DUMMYNET)
+#if IPFIREWALL
+#if DUMMYNET
 iphack:
-#endif
+#endif /* DUMMYNET */
        /*
         * Check if we want to allow this packet to be processed.
         * Consider it to be bad if not.
         */
-       if (fr_checkp) {
-               struct  mbuf    *m1 = m;
+       if (fw_enable && IPFW_LOADED) {
+#if IPFIREWALL_FORWARD
+               /*
+                * If we've been forwarded from the output side, then
+                * skip the firewall a second time
+                */
+               if (args->fwai_next_hop) {
+                       *ours = 1;
+                       return (IPINPUT_DONTCHAIN);
+               }
+#endif /* IPFIREWALL_FORWARD */
+               ip_input_cpout_args(args, &args1, &init);
+               args1.fwa_m = m;
+
+               i = ip_fw_chk_ptr(&args1);
+               m = args1.fwa_m;
+
+               if ((i & IP_FW_PORT_DENY_FLAG) || m == NULL) { /* drop */
+                       if (m)
+                               m_freem(m);
+                       ip_input_update_nstat(inifp, src_ip, 1, len);
+                       KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
+                       OSAddAtomic(1, &ipstat.ips_total);
+                       return (IPINPUT_FREED);
+               }
+               ip = mtod(m, struct ip *); /* just in case m changed */
+               *modm = m;
+               ip_input_cpin_args(&args1, args);
+
+               if (i == 0 && args->fwai_next_hop == NULL) { /* common case */
+                       goto pass;
+               }
+#if DUMMYNET
+               if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG) != 0) {
+                       /* Send packet to the appropriate pipe */
+                       ip_dn_io_ptr(m, i&0xffff, DN_TO_IP_IN, &args1,
+                           DN_CLIENT_IPFW);
+                       ip_input_update_nstat(inifp, src_ip, 1, len);
+                       KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
+                       OSAddAtomic(1, &ipstat.ips_total);
+                       return (IPINPUT_FREED);
+               }
+#endif /* DUMMYNET */
+#if IPDIVERT
+               if (i != 0 && (i & IP_FW_PORT_DYNT_FLAG) == 0) {
+                       /* Divert or tee packet */
+                       *div_info = i;
+                       *ours = 1;
+                       return (IPINPUT_DONTCHAIN);
+               }
+#endif
+#if IPFIREWALL_FORWARD
+               if (i == 0 && args->fwai_next_hop != NULL) {
+                       retval = IPINPUT_DONTCHAIN;
+                       goto pass;
+               }
+#endif
+               /*
+                * if we get here, the packet must be dropped
+                */
+               ip_input_update_nstat(inifp, src_ip, 1, len);
+               KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
+               m_freem(m);
+               OSAddAtomic(1, &ipstat.ips_total);
+               return (IPINPUT_FREED);
+       }
+#endif /* IPFIREWALL */
+#if IPSEC | IPFIREWALL
+pass:
+#endif
+       /*
+        * Process options and, if not destined for us,
+        * ship it on.  ip_dooptions returns 1 when an
+        * error was detected (causing an icmp message
+        * to be sent and the original packet to be freed).
+        */
+       ip_nhops = 0;           /* for source routed packets */
+#if IPFIREWALL
+       if (hlen > sizeof (struct ip) &&
+           ip_dooptions(m, 0, args->fwai_next_hop)) {
+#else /* !IPFIREWALL */
+       if (hlen > sizeof (struct ip) && ip_dooptions(m, 0, NULL)) {
+#endif /* !IPFIREWALL */
+               ip_input_update_nstat(inifp, src_ip, 1, len);
+               KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
+               OSAddAtomic(1, &ipstat.ips_total);
+               return (IPINPUT_FREED);
+       }
+
+       /*
+        * Don't chain fragmented packets as the process of determining
+        * if it is our fragment or someone else's plus the complexity of
+        * divert and fw args makes it harder to do chaining.
+        */
+       if (ip->ip_off & ~(IP_DF | IP_RF))
+               return (IPINPUT_DONTCHAIN);
+
+       /* Allow DHCP/BootP responses through */
+       if ((inifp->if_eflags & IFEF_AUTOCONFIGURING) &&
+           hlen == sizeof (struct ip) && ip->ip_p == IPPROTO_UDP) {
+               struct udpiphdr *ui;
+
+               if (m->m_len < sizeof (struct udpiphdr) &&
+                   (m = m_pullup(m, sizeof (struct udpiphdr))) == NULL) {
+                       OSAddAtomic(1, &udpstat.udps_hdrops);
+                       KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
+                       OSAddAtomic(1, &ipstat.ips_total);
+                       return (IPINPUT_FREED);
+               }
+               *modm = m;
+               ui = mtod(m, struct udpiphdr *);
+               if (ntohs(ui->ui_dport) == IPPORT_BOOTPC) {
+                       ip_setdstifaddr_info(m, inifp->if_index, NULL);
+                       return (IPINPUT_DONTCHAIN);
+               }
+       }
+
+       /* Avoid chaining raw sockets as ipsec checks occur later for them */
+       if (ip_protox[ip->ip_p]->pr_flags & PR_LASTHDR)
+               return (IPINPUT_DONTCHAIN);
+
+       return (retval);
+#if !defined(__i386__) && !defined(__x86_64__)
+bad:
+       m_freem(m);
+       return (IPINPUT_FREED);
+#endif
+}
+
+static void
+ip_input_second_pass(struct mbuf *m, struct ifnet *inifp, u_int32_t div_info,
+    int npkts_in_chain, int bytes_in_chain, struct ip_fw_in_args *args, int ours)
+{
+       unsigned int            checkif;
+       struct mbuf             *tmp_mbuf = NULL;
+       struct in_ifaddr        *ia = NULL;
+       struct in_addr          pkt_dst;
+       unsigned int            hlen;
+
+#if !IPFIREWALL
+#pragma unused (args)
+#endif
 
-               if (fr_checkp(ip, hlen, m->m_pkthdr.rcvif, 0, &m1) || !m1) {
-                       lck_mtx_unlock(ip_mutex);
+#if !IPDIVERT
+#pragma unused (div_info)
+#endif
+
+       struct ip *ip = mtod(m, struct ip *);
+       hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+
+       OSAddAtomic(npkts_in_chain, &ipstat.ips_total);
+
+       /*
+        * Naively assume we can attribute inbound data to the route we would
+        * use to send to this destination. Asymmetric routing breaks this
+        * assumption, but it still allows us to account for traffic from
+        * a remote node in the routing table.
+        * this has a very significant performance impact so we bypass
+        * if nstat_collect is disabled. We may also bypass if the
+        * protocol is tcp in the future because tcp will have a route that
+        * we can use to attribute the data to. That does mean we would not
+        * account for forwarded tcp traffic.
+        */
+       ip_input_update_nstat(inifp, ip->ip_src, npkts_in_chain,
+           bytes_in_chain);
+
+       if (ours)
+               goto ours;
+
+       /*
+        * Check our list of addresses, to see if the packet is for us.
+        * If we don't have any addresses, assume any unicast packet
+        * we receive might be for us (and let the upper layers deal
+        * with it).
+        */
+       tmp_mbuf = m;
+       if (TAILQ_EMPTY(&in_ifaddrhead)) {
+               while (tmp_mbuf) {
+                       if (!(tmp_mbuf->m_flags & (M_MCAST|M_BCAST))) {
+                               ip_setdstifaddr_info(tmp_mbuf, inifp->if_index,
+                                   NULL);
+                       }
+                       tmp_mbuf = mbuf_nextpkt(tmp_mbuf);
+               }
+               goto ours;
+       }
+       /*
+        * Cache the destination address of the packet; this may be
+        * changed by use of 'ipfw fwd'.
+        */
+#if IPFIREWALL
+       pkt_dst = args->fwai_next_hop == NULL ?
+           ip->ip_dst : args->fwai_next_hop->sin_addr;
+#else /* !IPFIREWALL */
+       pkt_dst = ip->ip_dst;
+#endif /* !IPFIREWALL */
+
+       /*
+        * Enable a consistency check between the destination address
+        * and the arrival interface for a unicast packet (the RFC 1122
+        * strong ES model) if IP forwarding is disabled and the packet
+        * is not locally generated and the packet is not subject to
+        * 'ipfw fwd'.
+        *
+        * XXX - Checking also should be disabled if the destination
+        * address is ipnat'ed to a different interface.
+        *
+        * XXX - Checking is incompatible with IP aliases added
+        * to the loopback interface instead of the interface where
+        * the packets are received.
+        */
+       checkif = ip_checkinterface && (ipforwarding == 0) &&
+           !(inifp->if_flags & IFF_LOOPBACK) &&
+           !(m->m_pkthdr.pkt_flags & PKTF_LOOP)
+#if IPFIREWALL
+           && (args->fwai_next_hop == NULL);
+#else /* !IPFIREWALL */
+               ;
+#endif /* !IPFIREWALL */
+
+       /*
+        * Check for exact addresses in the hash bucket.
+        */
+       lck_rw_lock_shared(in_ifaddr_rwlock);
+       TAILQ_FOREACH(ia, INADDR_HASH(pkt_dst.s_addr), ia_hash) {
+               /*
+                * If the address matches, verify that the packet
+                * arrived via the correct interface if checking is
+                * enabled.
+                */
+               if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr &&
+                   (!checkif || ia->ia_ifp == inifp)) {
+                       ip_input_setdst_chain(m, 0, ia);
+                       lck_rw_done(in_ifaddr_rwlock);
+                       goto ours;
+               }
+       }
+       lck_rw_done(in_ifaddr_rwlock);
+
+       /*
+        * Check for broadcast addresses.
+        *
+        * Only accept broadcast packets that arrive via the matching
+        * interface.  Reception of forwarded directed broadcasts would be
+        * handled via ip_forward() and ether_frameout() with the loopback
+        * into the stack for SIMPLEX interfaces handled by ether_frameout().
+        */
+       if (inifp->if_flags & IFF_BROADCAST) {
+               struct ifaddr *ifa;
+
+               ifnet_lock_shared(inifp);
+               TAILQ_FOREACH(ifa, &inifp->if_addrhead, ifa_link) {
+                       if (ifa->ifa_addr->sa_family != AF_INET) {
+                               continue;
+                       }
+                       ia = ifatoia(ifa);
+                       if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
+                           pkt_dst.s_addr || ia->ia_netbroadcast.s_addr ==
+                           pkt_dst.s_addr) {
+                               ip_input_setdst_chain(m, 0, ia);
+                               ifnet_lock_done(inifp);
+                               goto ours;
+                       }
+               }
+               ifnet_lock_done(inifp);
+       }
+
+       if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
+               struct in_multi *inm;
+               /*
+                * See if we belong to the destination multicast group on the
+                * arrival interface.
+                */
+               in_multihead_lock_shared();
+               IN_LOOKUP_MULTI(&ip->ip_dst, inifp, inm);
+               in_multihead_lock_done();
+               if (inm == NULL) {
+                       OSAddAtomic(npkts_in_chain, &ipstat.ips_notmember);
+                       m_freem_list(m);
+                       KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
                        return;
                }
-               ip = mtod(m = m1, struct ip *);
+               ip_input_setdst_chain(m, inifp->if_index, NULL);
+               INM_REMREF(inm);
+               goto ours;
        }
+
+       if (ip->ip_dst.s_addr == (u_int32_t)INADDR_BROADCAST ||
+           ip->ip_dst.s_addr == INADDR_ANY) {
+               ip_input_setdst_chain(m, inifp->if_index, NULL);
+               goto ours;
+       }
+
+       if (ip->ip_p == IPPROTO_UDP) {
+               struct udpiphdr *ui;
+               ui = mtod(m, struct udpiphdr *);
+               if (ntohs(ui->ui_dport) == IPPORT_BOOTPC) {
+                       goto ours;
+               }
+       }
+
+       tmp_mbuf = m;
+       struct mbuf *nxt_mbuf = NULL;
+       while (tmp_mbuf) {
+               nxt_mbuf = mbuf_nextpkt(tmp_mbuf);
+               /*
+                * Not for us; forward if possible and desirable.
+                */
+               mbuf_setnextpkt(tmp_mbuf, NULL);
+               if (ipforwarding == 0) {
+                       OSAddAtomic(1, &ipstat.ips_cantforward);
+                       m_freem(tmp_mbuf);
+               } else {
+#if IPFIREWALL
+                       ip_forward(tmp_mbuf, 0, args->fwai_next_hop);
+#else
+                       ip_forward(tmp_mbuf, 0, NULL);
+#endif
+               }
+               tmp_mbuf = nxt_mbuf;
+       }
+       KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
+       return;
+ours:
+       /*
+        * If offset or IP_MF are set, must reassemble.
+        */
+       if (ip->ip_off & ~(IP_DF | IP_RF)) {
+               VERIFY(npkts_in_chain == 1);
+               /*
+                * ip_reass() will return a different mbuf, and update
+                * the divert info in div_info and args->fwai_divert_rule.
+                */
+#if IPDIVERT
+               m = ip_reass(m, (u_int16_t *)&div_info, &args->fwai_divert_rule);
+#else
+               m = ip_reass(m);
+#endif
+               if (m == NULL)
+                       return;
+               ip = mtod(m, struct ip *);
+               /* Get the header length of the reassembled packet */
+               hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+#if IPDIVERT
+               /* Restore original checksum before diverting packet */
+               if (div_info != 0) {
+                       VERIFY(npkts_in_chain == 1);
+#if BYTE_ORDER != BIG_ENDIAN
+                       HTONS(ip->ip_len);
+                       HTONS(ip->ip_off);
+#endif
+                       ip->ip_sum = 0;
+                       ip->ip_sum = ip_cksum_hdr_in(m, hlen);
+#if BYTE_ORDER != BIG_ENDIAN
+                       NTOHS(ip->ip_off);
+                       NTOHS(ip->ip_len);
+#endif
+               }
+#endif
+       }
+
+       /*
+        * Further protocols expect the packet length to be w/o the
+        * IP header.
+        */
+       ip->ip_len -= hlen;
+
+#if IPDIVERT
+       /*
+        * Divert or tee packet to the divert protocol if required.
+        *
+        * If div_info is zero then cookie should be too, so we shouldn't
+        * need to clear them here.  Assume divert_packet() does so also.
+        */
+       if (div_info != 0) {
+               struct mbuf *clone = NULL;
+               VERIFY(npkts_in_chain == 1);
+
+               /* Clone packet if we're doing a 'tee' */
+               if (div_info & IP_FW_PORT_TEE_FLAG)
+                       clone = m_dup(m, M_DONTWAIT);
+
+               /* Restore packet header fields to original values */
+               ip->ip_len += hlen;
+
+#if BYTE_ORDER != BIG_ENDIAN
+               HTONS(ip->ip_len);
+               HTONS(ip->ip_off);
+#endif
+               /* Deliver packet to divert input routine */
+               OSAddAtomic(1, &ipstat.ips_delivered);
+               divert_packet(m, 1, div_info & 0xffff, args->fwai_divert_rule);
+
+               /* If 'tee', continue with original packet */
+               if (clone == NULL) {
+                       return;
+               }
+               m = clone;
+               ip = mtod(m, struct ip *);
+       }
+#endif
+
+#if IPSEC
+       /*
+        * enforce IPsec policy checking if we are seeing last header.
+        * note that we do not visit this with protocols with pcb layer
+        * code - like udp/tcp/raw ip.
+        */
+       if (ipsec_bypass == 0 && (ip_protox[ip->ip_p]->pr_flags & PR_LASTHDR)) {
+               VERIFY(npkts_in_chain == 1);
+               if (ipsec4_in_reject(m, NULL)) {
+                       IPSEC_STAT_INCREMENT(ipsecstat.in_polvio);
+                       goto bad;
+               }
+       }
+#endif /* IPSEC */
+
+       /*
+        * Switch out to protocol's input routine.
+        */
+       OSAddAtomic(npkts_in_chain, &ipstat.ips_delivered);
+
+#if IPFIREWALL
+       if (args->fwai_next_hop && ip->ip_p == IPPROTO_TCP) {
+               /* TCP needs IPFORWARD info if available */
+               struct m_tag *fwd_tag;
+               struct ip_fwd_tag *ipfwd_tag;
+
+               VERIFY(npkts_in_chain == 1);
+               fwd_tag = m_tag_create(KERNEL_MODULE_TAG_ID,
+                   KERNEL_TAG_TYPE_IPFORWARD, sizeof (*ipfwd_tag),
+                   M_NOWAIT, m);
+               if (fwd_tag == NULL)
+                       goto bad;
+
+               ipfwd_tag = (struct ip_fwd_tag *)(fwd_tag+1);
+               ipfwd_tag->next_hop = args->fwai_next_hop;
+
+               m_tag_prepend(m, fwd_tag);
+
+               KERNEL_DEBUG(DBG_LAYER_END, ip->ip_dst.s_addr,
+                   ip->ip_src.s_addr, ip->ip_p, ip->ip_off, ip->ip_len);
+
+               /* TCP deals with its own locking */
+               ip_proto_dispatch_in(m, hlen, ip->ip_p, 0);
+       } else {
+               KERNEL_DEBUG(DBG_LAYER_END, ip->ip_dst.s_addr,
+                   ip->ip_src.s_addr, ip->ip_p, ip->ip_off, ip->ip_len);
+
+               ip_input_dispatch_chain(m);
+
+       }
+#else /* !IPFIREWALL */
+       ip_input_dispatch_chain(m);
+
+#endif /* !IPFIREWALL */
+       KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
+       return;
+bad:
+       KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
+       m_freem(m);
+}
+
+void
+ip_input_process_list(struct mbuf *packet_list)
+{
+       pktchain_elm_t  pktchain_tbl[PKTTBL_SZ];
+
+       struct mbuf     *packet = NULL;
+       struct mbuf     *modm = NULL; /* modified mbuf */
+       int             retval = 0;
+       u_int32_t       div_info = 0;
+       int             ours = 0;
+       struct timeval start_tv;
+       int     num_pkts = 0;
+       int chain = 0;
+       struct ip_fw_in_args       args;
+
+       if (ip_chaining == 0) {
+               struct mbuf *m = packet_list;
+               if (ip_input_measure)
+                       net_perf_start_time(&net_perf, &start_tv);
+               while (m) {
+                       packet_list = mbuf_nextpkt(m);
+                       mbuf_setnextpkt(m, NULL);
+                       ip_input(m);
+                       m = packet_list;
+                       num_pkts++;
+               }
+               if (ip_input_measure)
+                       net_perf_measure_time(&net_perf, &start_tv, num_pkts);
+               return;
+       }
+       if (ip_input_measure)
+               net_perf_start_time(&net_perf, &start_tv);
+
+       bzero(&pktchain_tbl, sizeof(pktchain_tbl));
+restart_list_process:
+       chain = 0;
+       for (packet = packet_list; packet; packet = packet_list) {
+               packet_list = mbuf_nextpkt(packet);
+               mbuf_setnextpkt(packet, NULL);
+
+               num_pkts++;
+               modm = NULL;
+               div_info = 0;
+               bzero(&args, sizeof (args));
+
+               retval = ip_input_first_pass(packet, &div_info, &args,
+                   &ours, &modm);
+
+               if (retval == IPINPUT_DOCHAIN) {
+                       if (modm)
+                               packet = modm;
+                       packet = ip_chain_insert(packet, &pktchain_tbl[0]);
+                       if (packet == NULL) {
+                               ipstat.ips_rxc_chained++;
+                               chain++;
+                               if (chain > ip_chainsz)
+                                       break;
+                       } else {
+                               ipstat.ips_rxc_collisions++;
+                               break;
+                       }
+               } else if (retval == IPINPUT_DONTCHAIN) {
+                       /* in order to preserve order, exit from chaining */
+                       if (modm)
+                               packet = modm;
+                       ipstat.ips_rxc_notchain++;
+                       break;
+               } else {
+                       /* packet was freed or delivered, do nothing. */
+               }
+       }
+
+       /* do second pass here for pktchain_tbl */
+       if (chain)
+               ip_input_second_pass_loop_tbl(&pktchain_tbl[0], &args);
+
+       if (packet) {
+               /*
+                * equivalent update in chaining case if performed in
+                * ip_input_second_pass_loop_tbl().
+                */
+               if (ip_input_measure)
+                       net_perf_histogram(&net_perf, 1);
+
+               ip_input_second_pass(packet, packet->m_pkthdr.rcvif, div_info,
+                   1, packet->m_pkthdr.len, &args, ours);
+       }
+
+       if (packet_list)
+               goto restart_list_process;
+
+       if (ip_input_measure)
+               net_perf_measure_time(&net_perf, &start_tv, num_pkts);
+}
+/*
+ * Ip input routine.  Checksum and byte swap header.  If fragmented
+ * try to reassemble.  Process options.  Pass to next level.
+ */
+void
+ip_input(struct mbuf *m)
+{
+       struct ip *ip;
+       struct in_ifaddr *ia = NULL;
+       unsigned int hlen, checkif;
+       u_short sum = 0;
+       struct in_addr pkt_dst;
+#if IPFIREWALL
+       int i;
+       u_int32_t div_info = 0;         /* packet divert/tee info */
+#endif
+#if IPFIREWALL || DUMMYNET
+       struct ip_fw_args args;
+       struct m_tag    *tag;
+#endif
+       ipfilter_t inject_filter_ref = NULL;
+       struct ifnet *inifp;
+
+       /* Check if the mbuf is still valid after interface filter processing */
+       MBUF_INPUT_CHECK(m, m->m_pkthdr.rcvif);
+       inifp = m->m_pkthdr.rcvif;
+       VERIFY(inifp != NULL);
+
+       ipstat.ips_rxc_notlist++;
+
+       /* Perform IP header alignment fixup, if needed */
+       IP_HDR_ALIGNMENT_FIXUP(m, inifp, goto bad);
+
+       m->m_pkthdr.pkt_flags &= ~PKTF_FORWARDED;
+
+#if IPFIREWALL || DUMMYNET
+       bzero(&args, sizeof (struct ip_fw_args));
+
+       /*
+        * Don't bother searching for tag(s) if there's none.
+        */
+       if (SLIST_EMPTY(&m->m_pkthdr.tags))
+               goto ipfw_tags_done;
+
+       /* Grab info from mtags prepended to the chain */
+#if DUMMYNET
+       if ((tag = m_tag_locate(m, KERNEL_MODULE_TAG_ID,
+           KERNEL_TAG_TYPE_DUMMYNET, NULL)) != NULL) {
+               struct dn_pkt_tag *dn_tag;
+
+               dn_tag = (struct dn_pkt_tag *)(tag+1);
+               args.fwa_ipfw_rule = dn_tag->dn_ipfw_rule;
+               args.fwa_pf_rule = dn_tag->dn_pf_rule;
+
+               m_tag_delete(m, tag);
+       }
+#endif /* DUMMYNET */
+
+#if IPDIVERT
+       if ((tag = m_tag_locate(m, KERNEL_MODULE_TAG_ID,
+           KERNEL_TAG_TYPE_DIVERT, NULL)) != NULL) {
+               struct divert_tag *div_tag;
+
+               div_tag = (struct divert_tag *)(tag+1);
+               args.fwa_divert_rule = div_tag->cookie;
+
+               m_tag_delete(m, tag);
+       }
+#endif
+
+       if ((tag = m_tag_locate(m, KERNEL_MODULE_TAG_ID,
+           KERNEL_TAG_TYPE_IPFORWARD, NULL)) != NULL) {
+               struct ip_fwd_tag *ipfwd_tag;
+
+               ipfwd_tag = (struct ip_fwd_tag *)(tag+1);
+               args.fwa_next_hop = ipfwd_tag->next_hop;
+
+               m_tag_delete(m, tag);
+       }
+
+#if    DIAGNOSTIC
+       if (m == NULL || !(m->m_flags & M_PKTHDR))
+               panic("ip_input no HDR");
+#endif
+
+#if DUMMYNET
+       if (args.fwa_ipfw_rule || args.fwa_pf_rule) {
+               /* dummynet already filtered us */
+               ip = mtod(m, struct ip *);
+               hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+               inject_filter_ref = ipf_get_inject_filter(m);
+#if IPFIREWALL
+               if (args.fwa_ipfw_rule)
+                       goto iphack;
+#endif /* IPFIREWALL */
+               if (args.fwa_pf_rule)
+                       goto check_with_pf;
+       }
+#endif /* DUMMYNET */
+ipfw_tags_done:
+#endif /* IPFIREWALL || DUMMYNET */
+
+       /*
+        * No need to process packet twice if we've already seen it.
+        */
+       if (!SLIST_EMPTY(&m->m_pkthdr.tags))
+               inject_filter_ref = ipf_get_inject_filter(m);
+       if (inject_filter_ref != NULL) {
+               ip = mtod(m, struct ip *);
+               hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+
+               DTRACE_IP6(receive, struct mbuf *, m, struct inpcb *, NULL,
+                   struct ip *, ip, struct ifnet *, inifp,
+                   struct ip *, ip, struct ip6_hdr *, NULL);
+
+               ip->ip_len = ntohs(ip->ip_len) - hlen;
+               ip->ip_off = ntohs(ip->ip_off);
+               ip_proto_dispatch_in(m, hlen, ip->ip_p, inject_filter_ref);
+               return;
+       }
+
+       OSAddAtomic(1, &ipstat.ips_total);
+       if (m->m_pkthdr.len < sizeof (struct ip))
+               goto tooshort;
+
+       if (m->m_len < sizeof (struct ip) &&
+           (m = m_pullup(m, sizeof (struct ip))) == NULL) {
+               OSAddAtomic(1, &ipstat.ips_toosmall);
+               return;
+       }
+       ip = mtod(m, struct ip *);
+
+       KERNEL_DEBUG(DBG_LAYER_BEG, ip->ip_dst.s_addr, ip->ip_src.s_addr,
+           ip->ip_p, ip->ip_off, ip->ip_len);
+
+       if (IP_VHL_V(ip->ip_vhl) != IPVERSION) {
+               OSAddAtomic(1, &ipstat.ips_badvers);
+               goto bad;
+       }
+
+       hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+       if (hlen < sizeof (struct ip)) {        /* minimum header length */
+               OSAddAtomic(1, &ipstat.ips_badhlen);
+               goto bad;
+       }
+       if (hlen > m->m_len) {
+               if ((m = m_pullup(m, hlen)) == NULL) {
+                       OSAddAtomic(1, &ipstat.ips_badhlen);
+                       return;
+               }
+               ip = mtod(m, struct ip *);
+       }
+
+       /* 127/8 must not appear on wire - RFC1122 */
+       if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
+           (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
+               /*
+                * Allow for the following exceptions:
+                *
+                *   1. If the packet was sent to loopback (i.e. rcvif
+                *      would have been set earlier at output time.)
+                *
+                *   2. If the packet was sent out on loopback from a local
+                *      source address which belongs to a non-loopback
+                *      interface (i.e. rcvif may not necessarily be a
+                *      loopback interface, hence the test for PKTF_LOOP.)
+                *      Unlike IPv6, there is no interface scope ID, and
+                *      therefore we don't care so much about PKTF_IFINFO.
+                */
+               if (!(inifp->if_flags & IFF_LOOPBACK) &&
+                   !(m->m_pkthdr.pkt_flags & PKTF_LOOP)) {
+                       OSAddAtomic(1, &ipstat.ips_badaddr);
+                       goto bad;
+               }
+       }
+
+       /* IPv4 Link-Local Addresses as defined in RFC3927 */
+       if ((IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr)) ||
+           IN_LINKLOCAL(ntohl(ip->ip_src.s_addr)))) {
+               ip_linklocal_stat.iplls_in_total++;
+               if (ip->ip_ttl != MAXTTL) {
+                       OSAddAtomic(1, &ip_linklocal_stat.iplls_in_badttl);
+                       /* Silently drop link local traffic with bad TTL */
+                       if (!ip_linklocal_in_allowbadttl)
+                               goto bad;
+               }
+       }
+
+       sum = ip_cksum(m, hlen);
+       if (sum) {
+               goto bad;
+       }
+
+       DTRACE_IP6(receive, struct mbuf *, m, struct inpcb *, NULL,
+           struct ip *, ip, struct ifnet *, inifp,
+           struct ip *, ip, struct ip6_hdr *, NULL);
+
+       /*
+        * Naively assume we can attribute inbound data to the route we would
+        * use to send to this destination. Asymmetric routing breaks this
+        * assumption, but it still allows us to account for traffic from
+        * a remote node in the routing table.
+        * this has a very significant performance impact so we bypass
+        * if nstat_collect is disabled. We may also bypass if the
+        * protocol is tcp in the future because tcp will have a route that
+        * we can use to attribute the data to. That does mean we would not
+        * account for forwarded tcp traffic.
+        */
+       if (nstat_collect) {
+               struct rtentry *rt =
+                   ifnet_cached_rtlookup_inet(inifp, ip->ip_src);
+               if (rt != NULL) {
+                       nstat_route_rx(rt, 1, m->m_pkthdr.len, 0);
+                       rtfree(rt);
+               }
+       }
+
+       /*
+        * Convert fields to host representation.
+        */
+#if BYTE_ORDER != BIG_ENDIAN
+       NTOHS(ip->ip_len);
+#endif
+
+       if (ip->ip_len < hlen) {
+               OSAddAtomic(1, &ipstat.ips_badlen);
+               goto bad;
+       }
+
+#if BYTE_ORDER != BIG_ENDIAN
+       NTOHS(ip->ip_off);
+#endif
+       /*
+        * Check that the amount of data in the buffers
+        * is as at least much as the IP header would have us expect.
+        * Trim mbufs if longer than we expect.
+        * Drop packet if shorter than we expect.
+        */
+       if (m->m_pkthdr.len < ip->ip_len) {
+tooshort:
+               OSAddAtomic(1, &ipstat.ips_tooshort);
+               goto bad;
+       }
+       if (m->m_pkthdr.len > ip->ip_len) {
+               /*
+                * Invalidate hardware checksum info if ip_adj_clear_hwcksum
+                * is set; useful to handle buggy drivers.  Note that this
+                * should not be enabled by default, as we may get here due
+                * to link-layer padding.
+                */
+               if (ip_adj_clear_hwcksum &&
+                   (m->m_pkthdr.csum_flags & CSUM_DATA_VALID) &&
+                   !(inifp->if_flags & IFF_LOOPBACK) &&
+                   !(m->m_pkthdr.pkt_flags & PKTF_LOOP)) {
+                       m->m_pkthdr.csum_flags &= ~CSUM_DATA_VALID;
+                       m->m_pkthdr.csum_data = 0;
+                       ipstat.ips_adj_hwcsum_clr++;
+               }
+
+               ipstat.ips_adj++;
+               if (m->m_len == m->m_pkthdr.len) {
+                       m->m_len = ip->ip_len;
+                       m->m_pkthdr.len = ip->ip_len;
+               } else
+                       m_adj(m, ip->ip_len - m->m_pkthdr.len);
+       }
+
+       /* for consistency */
+       m->m_pkthdr.pkt_proto = ip->ip_p;
+
+#if DUMMYNET
+check_with_pf:
+#endif
+#if PF
+       /* Invoke inbound packet filter */
+       if (PF_IS_ENABLED) {
+               int error;
+#if DUMMYNET
+               error = pf_af_hook(inifp, NULL, &m, AF_INET, TRUE, &args);
+#else
+               error = pf_af_hook(inifp, NULL, &m, AF_INET, TRUE, NULL);
+#endif /* DUMMYNET */
+               if (error != 0 || m == NULL) {
+                       if (m != NULL) {
+                               panic("%s: unexpected packet %p\n",
+                                   __func__, m);
+                               /* NOTREACHED */
+                       }
+                       /* Already freed by callee */
+                       return;
+               }
+               ip = mtod(m, struct ip *);
+               hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+       }
+#endif /* PF */
+
+#if IPSEC
+       if (ipsec_bypass == 0 && ipsec_gethist(m, NULL))
+               goto pass;
+#endif
+
+#if IPFIREWALL
+#if DUMMYNET
+iphack:
+#endif /* DUMMYNET */
+       /*
+        * Check if we want to allow this packet to be processed.
+        * Consider it to be bad if not.
+        */
        if (fw_enable && IPFW_LOADED) {
 #if IPFIREWALL_FORWARD
                /*
                 * If we've been forwarded from the output side, then
                 * skip the firewall a second time
                 */
-               if (args.next_hop)
+               if (args.fwa_next_hop)
                        goto ours;
 #endif /* IPFIREWALL_FORWARD */
 
-               args.m = m;
-               lck_mtx_unlock(ip_mutex);
+               args.fwa_m = m;
 
                i = ip_fw_chk_ptr(&args);
-               m = args.m;
+               m = args.fwa_m;
 
-               if ( (i & IP_FW_PORT_DENY_FLAG) || m == NULL) { /* drop */
+               if ((i & IP_FW_PORT_DENY_FLAG) || m == NULL) { /* drop */
                        if (m)
                                m_freem(m);
                        return;
                }
                ip = mtod(m, struct ip *); /* just in case m changed */
-               if (i == 0 && args.next_hop == NULL) {  /* common case */
-                       lck_mtx_lock(ip_mutex);
+
+               if (i == 0 && args.fwa_next_hop == NULL) { /* common case */
                        goto pass;
                }
 #if DUMMYNET
-                if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG) != 0) {
+               if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG) != 0) {
                        /* Send packet to the appropriate pipe */
-                       ip_dn_io_ptr(m, i&0xffff, DN_TO_IP_IN, &args);
+                       ip_dn_io_ptr(m, i&0xffff, DN_TO_IP_IN, &args,
+                           DN_CLIENT_IPFW);
                        return;
                }
 #endif /* DUMMYNET */
 #if IPDIVERT
                if (i != 0 && (i & IP_FW_PORT_DYNT_FLAG) == 0) {
                        /* Divert or tee packet */
-                       lck_mtx_lock(ip_mutex);
                        div_info = i;
                        goto ours;
                }
 #endif
 #if IPFIREWALL_FORWARD
-               if (i == 0 && args.next_hop != NULL) {
-                       lck_mtx_lock(ip_mutex);
+               if (i == 0 && args.fwa_next_hop != NULL) {
                        goto pass;
                }
 #endif
@@ -747,8 +2099,10 @@ iphack:
                m_freem(m);
                return;
        }
+#endif /* IPFIREWALL */
+#if IPSEC | IPFIREWALL
 pass:
-
+#endif
        /*
         * Process options and, if not destined for us,
         * ship it on.  ip_dooptions returns 1 when an
@@ -756,36 +2110,36 @@ pass:
         * to be sent and the original packet to be freed).
         */
        ip_nhops = 0;           /* for source routed packets */
-       if (hlen > sizeof (struct ip) && ip_dooptions(m, 0, args.next_hop, &ipforward_rt)) {
-               lck_mtx_unlock(ip_mutex);
+#if IPFIREWALL
+       if (hlen > sizeof (struct ip) &&
+           ip_dooptions(m, 0, args.fwa_next_hop)) {
+#else /* !IPFIREWALL */
+       if (hlen > sizeof (struct ip) && ip_dooptions(m, 0, NULL)) {
+#endif /* !IPFIREWALL */
                return;
        }
 
-        /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no
-         * matter if it is destined to another node, or whether it is 
-         * a multicast one, RSVP wants it! and prevents it from being forwarded
-         * anywhere else. Also checks if the rsvp daemon is running before
-        * grabbing the packet.
-         */
-       if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 
-               goto ours;
-
        /*
         * Check our list of addresses, to see if the packet is for us.
         * If we don't have any addresses, assume any unicast packet
         * we receive might be for us (and let the upper layers deal
         * with it).
         */
-       if (TAILQ_EMPTY(&in_ifaddrhead) &&
-           (m->m_flags & (M_MCAST|M_BCAST)) == 0)
+       if (TAILQ_EMPTY(&in_ifaddrhead) && !(m->m_flags & (M_MCAST|M_BCAST))) {
+               ip_setdstifaddr_info(m, inifp->if_index, NULL);
                goto ours;
+       }
 
        /*
         * Cache the destination address of the packet; this may be
         * changed by use of 'ipfw fwd'.
         */
-       pkt_dst = args.next_hop == NULL ?
-           ip->ip_dst : args.next_hop->sin_addr;
+#if IPFIREWALL
+       pkt_dst = args.fwa_next_hop == NULL ?
+           ip->ip_dst : args.fwa_next_hop->sin_addr;
+#else /* !IPFIREWALL */
+       pkt_dst = ip->ip_dst;
+#endif /* !IPFIREWALL */
 
        /*
         * Enable a consistency check between the destination address
@@ -801,277 +2155,160 @@ pass:
         * to the loopback interface instead of the interface where
         * the packets are received.
         */
-       checkif = ip_checkinterface && (ipforwarding == 0) && 
-           ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) &&
-           (args.next_hop == NULL);
+       checkif = ip_checkinterface && (ipforwarding == 0) &&
+           !(inifp->if_flags & IFF_LOOPBACK) &&
+           !(m->m_pkthdr.pkt_flags & PKTF_LOOP)
+#if IPFIREWALL
+           && (args.fwa_next_hop == NULL);
+#else /* !IPFIREWALL */
+               ;
+#endif /* !IPFIREWALL */
 
-       lck_mtx_lock(rt_mtx);
-       TAILQ_FOREACH(ia, &in_ifaddrhead, ia_link) {
-#define        satosin(sa)     ((struct sockaddr_in *)(sa))
-
-               if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) {
-                       lck_mtx_unlock(rt_mtx);
-                       goto ours;
-               }
-               
+       /*
+        * Check for exact addresses in the hash bucket.
+        */
+       lck_rw_lock_shared(in_ifaddr_rwlock);
+       TAILQ_FOREACH(ia, INADDR_HASH(pkt_dst.s_addr), ia_hash) {
                /*
                 * If the address matches, verify that the packet
                 * arrived via the correct interface if checking is
                 * enabled.
                 */
-               if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 
-                   (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) {
-                       lck_mtx_unlock(rt_mtx);
+               if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr &&
+                   (!checkif || ia->ia_ifp == inifp)) {
+                       ip_setdstifaddr_info(m, 0, ia);
+                       lck_rw_done(in_ifaddr_rwlock);
                        goto ours;
                }
-               /*
-                * Only accept broadcast packets that arrive via the
-                * matching interface.  Reception of forwarded directed
-                * broadcasts would be handled via ip_forward() and
-                * ether_output() with the loopback into the stack for
-                * SIMPLEX interfaces handled by ether_output().
-                */
-               if ((!checkif || ia->ia_ifp == m->m_pkthdr.rcvif) &&
-                   ia->ia_ifp && ia->ia_ifp->if_flags & IFF_BROADCAST) {
+       }
+       lck_rw_done(in_ifaddr_rwlock);
+
+       /*
+        * Check for broadcast addresses.
+        *
+        * Only accept broadcast packets that arrive via the matching
+        * interface.  Reception of forwarded directed broadcasts would be
+        * handled via ip_forward() and ether_frameout() with the loopback
+        * into the stack for SIMPLEX interfaces handled by ether_frameout().
+        */
+       if (inifp->if_flags & IFF_BROADCAST) {
+               struct ifaddr *ifa;
+
+               ifnet_lock_shared(inifp);
+               TAILQ_FOREACH(ifa, &inifp->if_addrhead, ifa_link) {
+                       if (ifa->ifa_addr->sa_family != AF_INET) {
+                               continue;
+                       }
+                       ia = ifatoia(ifa);
                        if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
+                           pkt_dst.s_addr || ia->ia_netbroadcast.s_addr ==
                            pkt_dst.s_addr) {
-                               lck_mtx_unlock(rt_mtx);
+                               ip_setdstifaddr_info(m, 0, ia);
+                               ifnet_lock_done(inifp);
                                goto ours;
                        }
-                       if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) {
-                               lck_mtx_unlock(rt_mtx);
-                               goto ours;
-                       }
-               }
-       }
-       lck_mtx_unlock(rt_mtx);
-       if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
-               struct in_multi *inm;
-               if (ip_mrouter) {
-                       /*
-                        * If we are acting as a multicast router, all
-                        * incoming multicast packets are passed to the
-                        * kernel-level multicast forwarding function.
-                        * The packet is returned (relatively) intact; if
-                        * ip_mforward() returns a non-zero value, the packet
-                        * must be discarded, else it may be accepted below.
-                        */
-                       if (ip_mforward &&
-                           ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) {
-                               ipstat.ips_cantforward++;
-                               m_freem(m);
-                               lck_mtx_unlock(ip_mutex);
-                               return;
-                       }
-
-                       /*
-                        * The process-level routing daemon needs to receive
-                        * all multicast IGMP packets, whether or not this
-                        * host belongs to their destination groups.
-                        */
-                       if (ip->ip_p == IPPROTO_IGMP)
-                               goto ours;
-                       ipstat.ips_forward++;
                }
+               ifnet_lock_done(inifp);
+       }
+
+       if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
+               struct in_multi *inm;
                /*
                 * See if we belong to the destination multicast group on the
                 * arrival interface.
                 */
-               IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
+               in_multihead_lock_shared();
+               IN_LOOKUP_MULTI(&ip->ip_dst, inifp, inm);
+               in_multihead_lock_done();
                if (inm == NULL) {
-                       ipstat.ips_notmember++;
+                       OSAddAtomic(1, &ipstat.ips_notmember);
                        m_freem(m);
-                       lck_mtx_unlock(ip_mutex);
                        return;
                }
+               ip_setdstifaddr_info(m, inifp->if_index, NULL);
+               INM_REMREF(inm);
                goto ours;
        }
-       if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST)
-               goto ours;
-       if (ip->ip_dst.s_addr == INADDR_ANY)
+       if (ip->ip_dst.s_addr == (u_int32_t)INADDR_BROADCAST ||
+           ip->ip_dst.s_addr == INADDR_ANY) {
+               ip_setdstifaddr_info(m, inifp->if_index, NULL);
                goto ours;
+       }
 
        /* Allow DHCP/BootP responses through */
-       if (m->m_pkthdr.rcvif != NULL
-           && (m->m_pkthdr.rcvif->if_eflags & IFEF_AUTOCONFIGURING)
-           && hlen == sizeof(struct ip)
-           && ip->ip_p == IPPROTO_UDP) {
+       if ((inifp->if_eflags & IFEF_AUTOCONFIGURING) &&
+           hlen == sizeof (struct ip) && ip->ip_p == IPPROTO_UDP) {
                struct udpiphdr *ui;
-               if (m->m_len < sizeof(struct udpiphdr)
-                   && (m = m_pullup(m, sizeof(struct udpiphdr))) == 0) {
-                       udpstat.udps_hdrops++;
-                       lck_mtx_unlock(ip_mutex);
+
+               if (m->m_len < sizeof (struct udpiphdr) &&
+                   (m = m_pullup(m, sizeof (struct udpiphdr))) == NULL) {
+                       OSAddAtomic(1, &udpstat.udps_hdrops);
                        return;
                }
                ui = mtod(m, struct udpiphdr *);
                if (ntohs(ui->ui_dport) == IPPORT_BOOTPC) {
+                       ip_setdstifaddr_info(m, inifp->if_index, NULL);
                        goto ours;
                }
                ip = mtod(m, struct ip *); /* in case it changed */
        }
 
-#if defined(NFAITH) && 0 < NFAITH
-       /*
-        * FAITH(Firewall Aided Internet Translator)
-        */
-       if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
-               if (ip_keepfaith) {
-                       if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 
-                               goto ours;
-               }
-               m_freem(m);
-               lck_mtx_unlock(ip_mutex);
-               return;
-       }
-#endif
-       lck_mtx_unlock(ip_mutex);
        /*
         * Not for us; forward if possible and desirable.
         */
        if (ipforwarding == 0) {
-               ipstat.ips_cantforward++;
+               OSAddAtomic(1, &ipstat.ips_cantforward);
                m_freem(m);
        } else {
-               ip_forward(m, 0, args.next_hop, &ipforward_rt);
+#if IPFIREWALL
+               ip_forward(m, 0, args.fwa_next_hop);
+#else
+               ip_forward(m, 0, NULL);
+#endif
        }
        return;
 
 ours:
-#ifndef __APPLE__
-       /* Darwin does not have an if_data in ifaddr */
-       /* Count the packet in the ip address stats */
-       if (ia != NULL) {
-               ia->ia_ifa.if_ipackets++;
-               ia->ia_ifa.if_ibytes += m->m_pkthdr.len;
-       }
-#endif
-
        /*
         * If offset or IP_MF are set, must reassemble.
-        * Otherwise, nothing need be done.
-        * (We could look in the reassembly queue to see
-        * if the packet was previously fragmented,
-        * but it's not worth the time; just let them time out.)
         */
-       if (ip->ip_off & (IP_MF | IP_OFFMASK | IP_RF)) {
-
-               /* If maxnipq is 0, never accept fragments. */
-               if (maxnipq == 0) {
-                       ipstat.ips_fragments++;
-                       ipstat.ips_fragdropped++;
-                       goto bad;
-               }
-               
-               /*
-                * If we will exceed the number of fragments in queues, timeout the
-                * oldest fragemented packet to make space.
-                */
-               if (currentfrags >= maxfrags) {
-                       fp = TAILQ_LAST(&ipq_list, ipq_list);
-                       ipstat.ips_fragtimeout += fp->ipq_nfrags;
-                       
-                       if (ip->ip_id == fp->ipq_id &&
-                               ip->ip_src.s_addr == fp->ipq_src.s_addr &&
-                               ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
-                               ip->ip_p == fp->ipq_p) {
-                               /*
-                                * If we match the fragment queue we were going to
-                                * discard, drop this packet too.
-                                */
-                               ipstat.ips_fragdropped++;
-                               ip_freef(fp);
-                               goto bad;
-                       }
-                       
-                       ip_freef(fp);
-               }
-
-               sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id);
+       if (ip->ip_off & ~(IP_DF | IP_RF)) {
                /*
-                * Look for queue of fragments
-                * of this datagram.
-                */
-               for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next)
-                       if (ip->ip_id == fp->ipq_id &&
-                           ip->ip_src.s_addr == fp->ipq_src.s_addr &&
-                           ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
-                           ip->ip_p == fp->ipq_p)
-                               goto found;
-
-               /*
-                * Enforce upper bound on number of fragmented packets
-                * for which we attempt reassembly;
-                * If maxnipq is -1, accept all fragments without limitation.
-                */
-               if ((nipq > maxnipq) && (maxnipq > 0)) {
-                   /*
-                    * drop the oldest fragment before proceeding further
-                    */
-                   fp = TAILQ_LAST(&ipq_list, ipq_list);
-                   ipstat.ips_fragtimeout += fp->ipq_nfrags;
-                   ip_freef(fp);
-               }
-
-               fp = NULL;
-
-found:
-               /*
-                * Adjust ip_len to not reflect header,
-                * convert offset of this to bytes.
-                */
-               ip->ip_len -= hlen;
-               if (ip->ip_off & IP_MF) {
-                       /*
-                        * Make sure that fragments have a data length
-                                * that's a non-zero multiple of 8 bytes.
-                        */
-                       if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
-                               ipstat.ips_toosmall++; /* XXX */
-                               goto bad;
-                       }
-                       m->m_flags |= M_FRAG;
-               } else {
-                       /* Clear the flag in case packet comes from loopback */
-                       m->m_flags &= ~M_FRAG;
-               }
-               ip->ip_off <<= 3;
-
-               /*
-                * Attempt reassembly; if it succeeds, proceed.
                 * ip_reass() will return a different mbuf, and update
-                * the divert info in div_info and args.divert_rule.
+                * the divert info in div_info and args.fwa_divert_rule.
                 */
-                       ipstat.ips_fragments++;
-                       m->m_pkthdr.header = ip;
 #if IPDIVERT
-                       m = ip_reass(m,
-                           fp, &ipq[sum], &div_info, &args.divert_rule);
+               m = ip_reass(m, (u_int16_t *)&div_info, &args.fwa_divert_rule);
 #else
-                       m = ip_reass(m, fp, &ipq[sum]);
+               m = ip_reass(m);
 #endif
-                       if (m == 0) {
-                               lck_mtx_unlock(ip_mutex);
-                               return;
-                       }
-                       ipstat.ips_reassembled++;
-                       ip = mtod(m, struct ip *);
-                       /* Get the header length of the reassembled packet */
-                       hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+               if (m == NULL)
+                       return;
+               ip = mtod(m, struct ip *);
+               /* Get the header length of the reassembled packet */
+               hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 #if IPDIVERT
-                       /* Restore original checksum before diverting packet */
-                       if (div_info != 0) {
-                               ip->ip_len += hlen;
-                               HTONS(ip->ip_len);
-                               HTONS(ip->ip_off);
-                               ip->ip_sum = 0;
-                               ip->ip_sum = in_cksum(m, hlen);
-                               NTOHS(ip->ip_off);
-                               NTOHS(ip->ip_len);
-                               ip->ip_len -= hlen;
-                       }
+               /* Restore original checksum before diverting packet */
+               if (div_info != 0) {
+#if BYTE_ORDER != BIG_ENDIAN
+                       HTONS(ip->ip_len);
+                       HTONS(ip->ip_off);
 #endif
-               } else
-               ip->ip_len -= hlen;
+                       ip->ip_sum = 0;
+                       ip->ip_sum = ip_cksum_hdr_in(m, hlen);
+#if BYTE_ORDER != BIG_ENDIAN
+                       NTOHS(ip->ip_off);
+                       NTOHS(ip->ip_len);
+#endif
+               }
+#endif
+       }
+
+       /*
+        * Further protocols expect the packet length to be w/o the
+        * IP header.
+        */
+       ip->ip_len -= hlen;
 
 #if IPDIVERT
        /*
@@ -1084,24 +2321,24 @@ found:
                struct mbuf *clone = NULL;
 
                /* Clone packet if we're doing a 'tee' */
-               if ((div_info & IP_FW_PORT_TEE_FLAG) != 0)
+               if (div_info & IP_FW_PORT_TEE_FLAG)
                        clone = m_dup(m, M_DONTWAIT);
 
                /* Restore packet header fields to original values */
                ip->ip_len += hlen;
+
+#if BYTE_ORDER != BIG_ENDIAN
                HTONS(ip->ip_len);
                HTONS(ip->ip_off);
-
+#endif
                /* Deliver packet to divert input routine */
-               ipstat.ips_delivered++;
-               lck_mtx_unlock(ip_mutex);
-               divert_packet(m, 1, div_info & 0xffff, args.divert_rule);
+               OSAddAtomic(1, &ipstat.ips_delivered);
+               divert_packet(m, 1, div_info & 0xffff, args.fwa_divert_rule);
 
                /* If 'tee', continue with original packet */
                if (clone == NULL) {
                        return;
                }
-               lck_mtx_lock(ip_mutex);
                m = clone;
                ip = mtod(m, struct ip *);
        }
@@ -1113,61 +2350,136 @@ found:
         * note that we do not visit this with protocols with pcb layer
         * code - like udp/tcp/raw ip.
         */
-       if (ipsec_bypass == 0 && (ip_protox[ip->ip_p]->pr_flags & PR_LASTHDR) != 0) {
-               lck_mtx_lock(sadb_mutex);
+       if (ipsec_bypass == 0 && (ip_protox[ip->ip_p]->pr_flags & PR_LASTHDR)) {
                if (ipsec4_in_reject(m, NULL)) {
-                       ipsecstat.in_polvio++;
-                       lck_mtx_unlock(sadb_mutex);
+                       IPSEC_STAT_INCREMENT(ipsecstat.in_polvio);
                        goto bad;
                }
-               lck_mtx_unlock(sadb_mutex);
        }
-#endif
+#endif /* IPSEC */
 
        /*
         * Switch out to protocol's input routine.
         */
-       ipstat.ips_delivered++;
-       {
-               if (args.next_hop && ip->ip_p == IPPROTO_TCP) {
-                       /* TCP needs IPFORWARD info if available */
-                       struct m_tag *fwd_tag;
-                       struct ip_fwd_tag       *ipfwd_tag;
-                       
-                       fwd_tag = m_tag_alloc(KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_IPFORWARD,
-                                       sizeof(struct sockaddr_in), M_NOWAIT);
-                       if (fwd_tag == NULL) {
-                               goto bad;
-                       }
-                       
-                       ipfwd_tag = (struct ip_fwd_tag *)(fwd_tag+1);
-                       ipfwd_tag->next_hop = args.next_hop;
-
-                       m_tag_prepend(m, fwd_tag);
-       
-                       KERNEL_DEBUG(DBG_LAYER_END, ip->ip_dst.s_addr, 
-                            ip->ip_src.s_addr, ip->ip_p, ip->ip_off, ip->ip_len);
-       
-                       lck_mtx_unlock(ip_mutex);
-       
-                       /* TCP deals with its own locking */
-                       ip_proto_dispatch_in(m, hlen, ip->ip_p, 0);
-               } else {
-                       KERNEL_DEBUG(DBG_LAYER_END, ip->ip_dst.s_addr, 
-                            ip->ip_src.s_addr, ip->ip_p, ip->ip_off, ip->ip_len);
-               
-                       lck_mtx_unlock(ip_mutex);
-                       ip_proto_dispatch_in(m, hlen, ip->ip_p, 0);
+       OSAddAtomic(1, &ipstat.ips_delivered);
+
+#if IPFIREWALL
+       if (args.fwa_next_hop && ip->ip_p == IPPROTO_TCP) {
+               /* TCP needs IPFORWARD info if available */
+               struct m_tag *fwd_tag;
+               struct ip_fwd_tag *ipfwd_tag;
+
+               fwd_tag = m_tag_create(KERNEL_MODULE_TAG_ID,
+                   KERNEL_TAG_TYPE_IPFORWARD, sizeof (*ipfwd_tag),
+                   M_NOWAIT, m);
+               if (fwd_tag == NULL)
+                       goto bad;
+
+               ipfwd_tag = (struct ip_fwd_tag *)(fwd_tag+1);
+               ipfwd_tag->next_hop = args.fwa_next_hop;
+
+               m_tag_prepend(m, fwd_tag);
+
+               KERNEL_DEBUG(DBG_LAYER_END, ip->ip_dst.s_addr,
+                   ip->ip_src.s_addr, ip->ip_p, ip->ip_off, ip->ip_len);
+
+               /* TCP deals with its own locking */
+               ip_proto_dispatch_in(m, hlen, ip->ip_p, 0);
+       } else {
+               KERNEL_DEBUG(DBG_LAYER_END, ip->ip_dst.s_addr,
+                   ip->ip_src.s_addr, ip->ip_p, ip->ip_off, ip->ip_len);
+
+               if ((sw_lro) && (ip->ip_p == IPPROTO_TCP)) {
+                       m = tcp_lro(m, hlen);
+                       if (m == NULL)
+                               return;
                }
-               
-               return;
+
+               ip_proto_dispatch_in(m, hlen, ip->ip_p, 0);
+       }
+#else /* !IPFIREWALL */
+       if ((sw_lro) && (ip->ip_p == IPPROTO_TCP)) {
+               m = tcp_lro(m, hlen);
+               if (m == NULL)
+                       return;
        }
+       ip_proto_dispatch_in(m, hlen, ip->ip_p, 0);
+#endif /* !IPFIREWALL */
+       return;
+
 bad:
-       KERNEL_DEBUG(DBG_LAYER_END, 0,0,0,0,0);
-       lck_mtx_unlock(ip_mutex);
+       KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
        m_freem(m);
 }
 
+static void
+ipq_updateparams(void)
+{
+       lck_mtx_assert(&ipqlock, LCK_MTX_ASSERT_OWNED);
+       /*
+        * -1 for unlimited allocation.
+        */
+       if (maxnipq < 0)
+               ipq_limit = 0;
+       /*
+        * Positive number for specific bound.
+        */
+       if (maxnipq > 0)
+               ipq_limit = maxnipq;
+       /*
+        * Zero specifies no further fragment queue allocation -- set the
+        * bound very low, but rely on implementation elsewhere to actually
+        * prevent allocation and reclaim current queues.
+        */
+       if (maxnipq == 0)
+               ipq_limit = 1;
+       /*
+        * Arm the purge timer if not already and if there's work to do
+        */
+       frag_sched_timeout();
+}
+
+static int
+sysctl_maxnipq SYSCTL_HANDLER_ARGS
+{
+#pragma unused(arg1, arg2)
+       int error, i;
+
+       lck_mtx_lock(&ipqlock);
+       i = maxnipq;
+       error = sysctl_handle_int(oidp, &i, 0, req);
+       if (error || req->newptr == USER_ADDR_NULL)
+               goto done;
+       /* impose bounds */
+       if (i < -1 || i > (nmbclusters / 4)) {
+               error = EINVAL;
+               goto done;
+       }
+       maxnipq = i;
+       ipq_updateparams();
+done:
+       lck_mtx_unlock(&ipqlock);
+       return (error);
+}
+
+static int
+sysctl_maxfragsperpacket SYSCTL_HANDLER_ARGS
+{
+#pragma unused(arg1, arg2)
+       int error, i;
+
+       lck_mtx_lock(&ipqlock);
+       i = maxfragsperpacket;
+       error = sysctl_handle_int(oidp, &i, 0, req);
+       if (error || req->newptr == USER_ADDR_NULL)
+               goto done;
+       maxfragsperpacket = i;
+       ipq_updateparams();     /* see if we need to arm timer */
+done:
+       lck_mtx_unlock(&ipqlock);
+       return (error);
+}
+
 /*
  * Take incoming datagram fragment and try to reassemble it into
  * whole datagram.  If a chain for reassembly of this datagram already
@@ -1175,32 +2487,176 @@ bad:
  *
  * When IPDIVERT enabled, keep additional state with each packet that
  * tells us if we need to divert or tee the packet we're building.
+ *
+ * The IP header is *NOT* adjusted out of iplen.
  */
-
 static struct mbuf *
 #if IPDIVERT
-ip_reass(m, fp, where, divinfo, divcookie)
-#else
-ip_reass(m, fp, where)
-#endif
-       register struct mbuf *m;
-       register struct ipq *fp;
-       struct   ipq    *where;
-#if IPDIVERT
+ip_reass(struct mbuf *m,
 #ifdef IPDIVERT_44
-       u_int32_t *divinfo;
-#else
-       u_int16_t *divinfo;
+    u_int32_t *divinfo,
+#else /* IPDIVERT_44 */
+    u_int16_t *divinfo,
+#endif /* IPDIVERT_44 */
+    u_int16_t *divcookie)
+#else /* IPDIVERT */
+ip_reass(struct mbuf *m)
+#endif /* IPDIVERT */
+{
+       struct ip *ip;
+       struct mbuf *p, *q, *nq, *t;
+       struct ipq *fp = NULL;
+       struct ipqhead *head;
+       int i, hlen, next;
+       u_int8_t ecn, ecn0;
+       uint32_t csum, csum_flags;
+       uint16_t hash;
+       struct fq_head dfq;
+
+       MBUFQ_INIT(&dfq);       /* for deferred frees */
+
+       /* If maxnipq or maxfragsperpacket is 0, never accept fragments. */
+       if (maxnipq == 0 || maxfragsperpacket == 0) {
+               ipstat.ips_fragments++;
+               ipstat.ips_fragdropped++;
+               m_freem(m);
+               if (nipq > 0) {
+                       lck_mtx_lock(&ipqlock);
+                       frag_sched_timeout();   /* purge stale fragments */
+                       lck_mtx_unlock(&ipqlock);
+               }
+               return (NULL);
+       }
+
+       ip = mtod(m, struct ip *);
+       hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+
+       lck_mtx_lock(&ipqlock);
+
+       hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id);
+       head = &ipq[hash];
+
+       /*
+        * Look for queue of fragments
+        * of this datagram.
+        */
+       TAILQ_FOREACH(fp, head, ipq_list) {
+               if (ip->ip_id == fp->ipq_id &&
+                   ip->ip_src.s_addr == fp->ipq_src.s_addr &&
+                   ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
+#if CONFIG_MACF_NET
+                   mac_ipq_label_compare(m, fp) &&
+#endif
+                   ip->ip_p == fp->ipq_p)
+                       goto found;
+       }
+
+       fp = NULL;
+
+       /*
+        * Attempt to trim the number of allocated fragment queues if it
+        * exceeds the administrative limit.
+        */
+       if ((nipq > (unsigned)maxnipq) && (maxnipq > 0)) {
+               /*
+                * drop something from the tail of the current queue
+                * before proceeding further
+                */
+               struct ipq *fq = TAILQ_LAST(head, ipqhead);
+               if (fq == NULL) {   /* gak */
+                       for (i = 0; i < IPREASS_NHASH; i++) {
+                               struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead);
+                               if (r) {
+                                       ipstat.ips_fragtimeout += r->ipq_nfrags;
+                                       frag_freef(&ipq[i], r);
+                                       break;
+                               }
+                       }
+               } else {
+                       ipstat.ips_fragtimeout += fq->ipq_nfrags;
+                       frag_freef(head, fq);
+               }
+       }
+
+found:
+       /*
+        * Leverage partial checksum offload for IP fragments.  Narrow down
+        * the scope to cover only UDP without IP options, as that is the
+        * most common case.
+        *
+        * Perform 1's complement adjustment of octets that got included/
+        * excluded in the hardware-calculated checksum value.  Ignore cases
+        * where the value includes or excludes the IP header span, as the
+        * sum for those octets would already be 0xffff and thus no-op.
+        */
+       if (ip->ip_p == IPPROTO_UDP && hlen == sizeof (struct ip) &&
+           (m->m_pkthdr.csum_flags &
+           (CSUM_DATA_VALID | CSUM_PARTIAL | CSUM_PSEUDO_HDR)) ==
+           (CSUM_DATA_VALID | CSUM_PARTIAL)) {
+               uint32_t start;
+
+               start = m->m_pkthdr.csum_rx_start;
+               csum = m->m_pkthdr.csum_rx_val;
+
+               if (start != 0 && start != hlen) {
+#if BYTE_ORDER != BIG_ENDIAN
+                       if (start < hlen) {
+                               HTONS(ip->ip_len);
+                               HTONS(ip->ip_off);
+                       }
 #endif
-       u_int16_t *divcookie;
+                       /* callee folds in sum */
+                       csum = m_adj_sum16(m, start, hlen, csum);
+#if BYTE_ORDER != BIG_ENDIAN
+                       if (start < hlen) {
+                               NTOHS(ip->ip_off);
+                               NTOHS(ip->ip_len);
+                       }
 #endif
-{
-       struct ip *ip = mtod(m, struct ip *);
-       register struct mbuf *p = 0, *q, *nq;
-       struct mbuf *t;
-       int hlen = IP_VHL_HL(ip->ip_vhl) << 2;
-       int i, next;
+               }
+               csum_flags = m->m_pkthdr.csum_flags;
+       } else {
+               csum = 0;
+               csum_flags = 0;
+       }
 
+       /* Invalidate checksum */
+       m->m_pkthdr.csum_flags &= ~CSUM_DATA_VALID;
+
+       ipstat.ips_fragments++;
+
+       /*
+        * Adjust ip_len to not reflect header,
+        * convert offset of this to bytes.
+        */
+       ip->ip_len -= hlen;
+       if (ip->ip_off & IP_MF) {
+               /*
+                * Make sure that fragments have a data length
+                * that's a non-zero multiple of 8 bytes.
+                */
+               if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
+                       OSAddAtomic(1, &ipstat.ips_toosmall);
+                       /*
+                        * Reassembly queue may have been found if previous
+                        * fragments were valid; given that this one is bad,
+                        * we need to drop it.  Make sure to set fp to NULL
+                        * if not already, since we don't want to decrement
+                        * ipq_nfrags as it doesn't include this packet.
+                        */
+                       fp = NULL;
+                       goto dropfrag;
+               }
+               m->m_flags |= M_FRAG;
+       } else {
+               /* Clear the flag in case packet comes from loopback */
+               m->m_flags &= ~M_FRAG;
+       }
+       ip->ip_off <<= 3;
+
+       m->m_pkthdr.pkt_hdr = ip;
+
+       /* Previous ip_reass() started here. */
        /*
         * Presence of header sizes in mbufs
         * would confuse code below.
@@ -1208,16 +2664,22 @@ ip_reass(m, fp, where)
        m->m_data += hlen;
        m->m_len -= hlen;
 
-       if (m->m_pkthdr.csum_flags & CSUM_TCP_SUM16) 
-                       m->m_pkthdr.csum_flags = 0;
        /*
         * If first fragment to arrive, create a reassembly queue.
         */
-       if (fp == 0) {
-               if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL)
+       if (fp == NULL) {
+               fp = ipq_alloc(M_DONTWAIT);
+               if (fp == NULL)
                        goto dropfrag;
-               fp = mtod(t, struct ipq *);
-               insque((void*)fp, (void*)where);
+#if CONFIG_MACF_NET
+               if (mac_ipq_label_init(fp, M_NOWAIT) != 0) {
+                       ipq_free(fp);
+                       fp = NULL;
+                       goto dropfrag;
+               }
+               mac_ipq_label_associate(m, fp);
+#endif
+               TAILQ_INSERT_HEAD(head, fp, ipq_list);
                nipq++;
                fp->ipq_nfrags = 1;
                fp->ipq_ttl = IPFRAGTTL;
@@ -1227,21 +2689,56 @@ ip_reass(m, fp, where)
                fp->ipq_dst = ip->ip_dst;
                fp->ipq_frags = m;
                m->m_nextpkt = NULL;
+               /*
+                * If the first fragment has valid checksum offload
+                * info, the rest of fragments are eligible as well.
+                */
+               if (csum_flags != 0) {
+                       fp->ipq_csum = csum;
+                       fp->ipq_csum_flags = csum_flags;
+               }
 #if IPDIVERT
+               /*
+                * Transfer firewall instructions to the fragment structure.
+                * Only trust info in the fragment at offset 0.
+                */
+               if (ip->ip_off == 0) {
 #ifdef IPDIVERT_44
-               fp->ipq_div_info = 0;
+                       fp->ipq_div_info = *divinfo;
 #else
-               fp->ipq_divert = 0;
-#endif
-               fp->ipq_div_cookie = 0;
+                       fp->ipq_divert = *divinfo;
 #endif
-               TAILQ_INSERT_HEAD(&ipq_list, fp, ipq_list);
-               goto inserted;
+                       fp->ipq_div_cookie = *divcookie;
+               }
+               *divinfo = 0;
+               *divcookie = 0;
+#endif /* IPDIVERT */
+               m = NULL;       /* nothing to return */
+               goto done;
        } else {
                fp->ipq_nfrags++;
+#if CONFIG_MACF_NET
+               mac_ipq_label_update(m, fp);
+#endif
        }
 
-#define GETIP(m)       ((struct ip*)((m)->m_pkthdr.header))
+#define        GETIP(m)        ((struct ip *)((m)->m_pkthdr.pkt_hdr))
+
+       /*
+        * Handle ECN by comparing this segment with the first one;
+        * if CE is set, do not lose CE.
+        * drop if CE and not-ECT are mixed for the same packet.
+        */
+       ecn = ip->ip_tos & IPTOS_ECN_MASK;
+       ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK;
+       if (ecn == IPTOS_ECN_CE) {
+               if (ecn0 == IPTOS_ECN_NOTECT)
+                       goto dropfrag;
+               if (ecn0 != IPTOS_ECN_CE)
+                       GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE;
+       }
+       if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT)
+               goto dropfrag;
 
        /*
         * Find a segment which begins after this one does.
@@ -1256,7 +2753,7 @@ ip_reass(m, fp, where)
         * segment.  If it provides all of our data, drop us, otherwise
         * stick new segment in the proper place.
         *
-        * If some of the data is dropped from the the preceding
+        * If some of the data is dropped from the preceding
         * segment, then it's checksum is invalidated.
         */
        if (p) {
@@ -1265,7 +2762,7 @@ ip_reass(m, fp, where)
                        if (i >= ip->ip_len)
                                goto dropfrag;
                        m_adj(m, i);
-                       m->m_pkthdr.csum_flags = 0;
+                       fp->ipq_csum_flags = 0;
                        ip->ip_off += i;
                        ip->ip_len -= i;
                }
@@ -1281,25 +2778,32 @@ ip_reass(m, fp, where)
         * if they are completely covered, dequeue them.
         */
        for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off;
-            q = nq) {
-               i = (ip->ip_off + ip->ip_len) -
-                   GETIP(q)->ip_off;
+           q = nq) {
+               i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off;
                if (i < GETIP(q)->ip_len) {
                        GETIP(q)->ip_len -= i;
                        GETIP(q)->ip_off += i;
                        m_adj(q, i);
-                       q->m_pkthdr.csum_flags = 0;
+                       fp->ipq_csum_flags = 0;
                        break;
                }
                nq = q->m_nextpkt;
                m->m_nextpkt = nq;
                ipstat.ips_fragdropped++;
                fp->ipq_nfrags--;
-               m_freem(q);
+               /* defer freeing until after lock is dropped */
+               MBUFQ_ENQUEUE(&dfq, q);
        }
 
-inserted:
-       currentfrags++;
+       /*
+        * If this fragment contains similar checksum offload info
+        * as that of the existing ones, accumulate checksum.  Otherwise,
+        * invalidate checksum offload info for the entire datagram.
+        */
+       if (csum_flags != 0 && csum_flags == fp->ipq_csum_flags)
+               fp->ipq_csum += csum;
+       else if (fp->ipq_csum_flags != 0)
+               fp->ipq_csum_flags = 0;
 
 #if IPDIVERT
        /*
@@ -1308,15 +2812,15 @@ inserted:
         */
        if (ip->ip_off == 0) {
 #ifdef IPDIVERT_44
-       fp->ipq_div_info = *divinfo;
+               fp->ipq_div_info = *divinfo;
 #else
-       fp->ipq_divert = *divinfo;
+               fp->ipq_divert = *divinfo;
 #endif
-       fp->ipq_div_cookie = *divcookie;
+               fp->ipq_div_cookie = *divcookie;
        }
        *divinfo = 0;
        *divcookie = 0;
-#endif
+#endif /* IPDIVERT */
 
        /*
         * Check for complete reassembly and perform frag per packet
@@ -1333,9 +2837,10 @@ inserted:
                if (GETIP(q)->ip_off != next) {
                        if (fp->ipq_nfrags > maxfragsperpacket) {
                                ipstat.ips_fragdropped += fp->ipq_nfrags;
-                               ip_freef(fp);
+                               frag_freef(head, fp);
                        }
-                       return (0);
+                       m = NULL;       /* nothing to return */
+                       goto done;
                }
                next += GETIP(q)->ip_len;
        }
@@ -1343,9 +2848,10 @@ inserted:
        if (p->m_flags & M_FRAG) {
                if (fp->ipq_nfrags > maxfragsperpacket) {
                        ipstat.ips_fragdropped += fp->ipq_nfrags;
-                       ip_freef(fp);
+                       frag_freef(head, fp);
                }
-               return (0);
+               m = NULL;               /* nothing to return */
+               goto done;
        }
 
        /*
@@ -1356,8 +2862,9 @@ inserted:
        if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) {
                ipstat.ips_toolong++;
                ipstat.ips_fragdropped += fp->ipq_nfrags;
-               ip_freef(fp);
-               return (0);
+               frag_freef(head, fp);
+               m = NULL;               /* nothing to return */
+               goto done;
        }
 
        /*
@@ -1365,22 +2872,39 @@ inserted:
         */
        m = q;
        t = m->m_next;
-       m->m_next = 0;
+       m->m_next = NULL;
        m_cat(m, t);
        nq = q->m_nextpkt;
-       q->m_nextpkt = 0;
+       q->m_nextpkt = NULL;
        for (q = nq; q != NULL; q = nq) {
                nq = q->m_nextpkt;
                q->m_nextpkt = NULL;
-               if (q->m_pkthdr.csum_flags & CSUM_TCP_SUM16) 
-                       m->m_pkthdr.csum_flags = 0;
-               else {
-                       m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags;
-                       m->m_pkthdr.csum_data += q->m_pkthdr.csum_data;
-               }
                m_cat(m, q);
        }
 
+       /*
+        * Store partial hardware checksum info from the fragment queue;
+        * the receive start offset is set to 20 bytes (see code at the
+        * top of this routine.)
+        */
+       if (fp->ipq_csum_flags != 0) {
+               csum = fp->ipq_csum;
+
+               ADDCARRY(csum);
+
+               m->m_pkthdr.csum_rx_val = csum;
+               m->m_pkthdr.csum_rx_start = sizeof (struct ip);
+               m->m_pkthdr.csum_flags = fp->ipq_csum_flags;
+       } else if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) ||
+           (m->m_pkthdr.pkt_flags & PKTF_LOOP)) {
+               /* loopback checksums are always OK */
+               m->m_pkthdr.csum_data = 0xffff;
+               m->m_pkthdr.csum_flags &= ~CSUM_PARTIAL;
+               m->m_pkthdr.csum_flags =
+                   CSUM_DATA_VALID | CSUM_PSEUDO_HDR |
+                   CSUM_IP_CHECKED | CSUM_IP_VALID;
+       }
+
 #if IPDIVERT
        /*
         * Extract firewall instructions from the fragment structure.
@@ -1391,44 +2915,69 @@ inserted:
        *divinfo = fp->ipq_divert;
 #endif
        *divcookie = fp->ipq_div_cookie;
-#endif
+#endif /* IPDIVERT */
 
+#if CONFIG_MACF_NET
+       mac_mbuf_label_associate_ipq(fp, m);
+       mac_ipq_label_destroy(fp);
+#endif
        /*
-        * Create header for new ip packet by
-        * modifying header of first packet;
-        * dequeue and discard fragment reassembly header.
+        * Create header for new ip packet by modifying header of first
+        * packet; dequeue and discard fragment reassembly header.
         * Make header visible.
         */
-       ip->ip_len = next;
+       ip->ip_len = (IP_VHL_HL(ip->ip_vhl) << 2) + next;
        ip->ip_src = fp->ipq_src;
        ip->ip_dst = fp->ipq_dst;
-       remque((void*)fp);
-       TAILQ_REMOVE(&ipq_list, fp, ipq_list);
-       currentfrags -= fp->ipq_nfrags;
-       nipq--;
-       (void) m_free(dtom(fp));
+
+       fp->ipq_frags = NULL;   /* return to caller as 'm' */
+       frag_freef(head, fp);
+       fp = NULL;
+
        m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2);
        m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2);
        /* some debugging cruft by sklower, below, will go away soon */
-       if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
-               register int plen = 0;
-               for (t = m; t; t = t->m_next)
-                       plen += t->m_len;
-               m->m_pkthdr.len = plen;
-       }
+       if (m->m_flags & M_PKTHDR)      /* XXX this should be done elsewhere */
+               m_fixhdr(m);
+       ipstat.ips_reassembled++;
+
+       /* arm the purge timer if not already and if there's work to do */
+       frag_sched_timeout();
+       lck_mtx_unlock(&ipqlock);
+       /* perform deferred free (if needed) now that lock is dropped */
+       if (!MBUFQ_EMPTY(&dfq))
+               MBUFQ_DRAIN(&dfq);
+       VERIFY(MBUFQ_EMPTY(&dfq));
        return (m);
 
+done:
+       VERIFY(m == NULL);
+       /* arm the purge timer if not already and if there's work to do */
+       frag_sched_timeout();
+       lck_mtx_unlock(&ipqlock);
+       /* perform deferred free (if needed) */
+       if (!MBUFQ_EMPTY(&dfq))
+               MBUFQ_DRAIN(&dfq);
+       VERIFY(MBUFQ_EMPTY(&dfq));
+       return (NULL);
+
 dropfrag:
 #if IPDIVERT
        *divinfo = 0;
        *divcookie = 0;
-#endif
+#endif /* IPDIVERT */
        ipstat.ips_fragdropped++;
-       if (fp != 0)
+       if (fp != NULL)
                fp->ipq_nfrags--;
+       /* arm the purge timer if not already and if there's work to do */
+       frag_sched_timeout();
+       lck_mtx_unlock(&ipqlock);
        m_freem(m);
-       return (0);
-
+       /* perform deferred free (if needed) */
+       if (!MBUFQ_EMPTY(&dfq))
+               MBUFQ_DRAIN(&dfq);
+       VERIFY(MBUFQ_EMPTY(&dfq));
+       return (NULL);
 #undef GETIP
 }
 
@@ -1437,38 +2986,47 @@ dropfrag:
  * associated datagrams.
  */
 static void
-ip_freef(fp)
-       struct ipq *fp;
+frag_freef(struct ipqhead *fhp, struct ipq *fp)
 {
-       currentfrags -= fp->ipq_nfrags;
-       m_freem_list(fp->ipq_frags);
-       remque((void*)fp);
-       TAILQ_REMOVE(&ipq_list, fp, ipq_list);
-       (void) m_free(dtom(fp));
+       lck_mtx_assert(&ipqlock, LCK_MTX_ASSERT_OWNED);
+
+       fp->ipq_nfrags = 0;
+       if (fp->ipq_frags != NULL) {
+               m_freem_list(fp->ipq_frags);
+               fp->ipq_frags = NULL;
+       }
+       TAILQ_REMOVE(fhp, fp, ipq_list);
        nipq--;
+       ipq_free(fp);
 }
 
 /*
- * IP timer processing;
- * if a timer expires on a reassembly
- * queue, discard it.
+ * IP reassembly timer processing
  */
-void
-ip_slowtimo()
+static void
+frag_timeout(void *arg)
 {
-       register struct ipq *fp;
+#pragma unused(arg)
+       struct ipq *fp;
        int i;
-       lck_mtx_lock(ip_mutex);
+
+       /*
+        * Update coarse-grained networking timestamp (in sec.); the idea
+        * is to piggy-back on the timeout callout to update the counter
+        * returnable via net_uptime().
+        */
+       net_update_uptime();
+
+       lck_mtx_lock(&ipqlock);
        for (i = 0; i < IPREASS_NHASH; i++) {
-               fp = ipq[i].next;
-               if (fp == 0)
-                       continue;
-               while (fp != &ipq[i]) {
-                       --fp->ipq_ttl;
-                       fp = fp->next;
-                       if (fp->prev->ipq_ttl == 0) {
-                               ipstat.ips_fragtimeout += fp->prev->ipq_nfrags;
-                               ip_freef(fp->prev);
+               for (fp = TAILQ_FIRST(&ipq[i]); fp; ) {
+                       struct ipq *fpp;
+
+                       fpp = fp;
+                       fp = TAILQ_NEXT(fp, ipq_list);
+                       if (--fpp->ipq_ttl == 0) {
+                               ipstat.ips_fragtimeout += fpp->ipq_nfrags;
+                               frag_freef(&ipq[i], fpp);
                        }
                }
        }
@@ -1477,37 +3035,93 @@ ip_slowtimo()
         * (due to the limit being lowered), drain off
         * enough to get down to the new limit.
         */
-       if (maxnipq >= 0 && nipq > maxnipq) {
-       for (i = 0; i < IPREASS_NHASH; i++) {
-                       while (nipq > maxnipq &&
-                               (ipq[i].next != &ipq[i])) {
+       if (maxnipq >= 0 && nipq > (unsigned)maxnipq) {
+               for (i = 0; i < IPREASS_NHASH; i++) {
+                       while (nipq > (unsigned)maxnipq &&
+                           !TAILQ_EMPTY(&ipq[i])) {
                                ipstat.ips_fragdropped +=
-                                   ipq[i].next->ipq_nfrags;
-                               ip_freef(ipq[i].next);
+                                   TAILQ_FIRST(&ipq[i])->ipq_nfrags;
+                               frag_freef(&ipq[i], TAILQ_FIRST(&ipq[i]));
                        }
                }
        }
-       ipflow_slowtimo();
-       lck_mtx_unlock(ip_mutex);
+       /* re-arm the purge timer if there's work to do */
+       frag_timeout_run = 0;
+       frag_sched_timeout();
+       lck_mtx_unlock(&ipqlock);
+}
+
+static void
+frag_sched_timeout(void)
+{
+       lck_mtx_assert(&ipqlock, LCK_MTX_ASSERT_OWNED);
+
+       if (!frag_timeout_run && nipq > 0) {
+               frag_timeout_run = 1;
+               timeout(frag_timeout, NULL, hz);
+       }
+}
+
+/*
+ * Drain off all datagram fragments.
+ */
+static void
+frag_drain(void)
+{
+       int i;
+
+       lck_mtx_lock(&ipqlock);
+       for (i = 0; i < IPREASS_NHASH; i++) {
+               while (!TAILQ_EMPTY(&ipq[i])) {
+                       ipstat.ips_fragdropped +=
+                           TAILQ_FIRST(&ipq[i])->ipq_nfrags;
+                       frag_freef(&ipq[i], TAILQ_FIRST(&ipq[i]));
+               }
+       }
+       lck_mtx_unlock(&ipqlock);
+}
+
+static struct ipq *
+ipq_alloc(int how)
+{
+       struct mbuf *t;
+       struct ipq *fp;
+
+       /*
+        * See comments in ipq_updateparams().  Keep the count separate
+        * from nipq since the latter represents the elements already
+        * in the reassembly queues.
+        */
+       if (ipq_limit > 0 && ipq_count > ipq_limit)
+               return (NULL);
+
+       t = m_get(how, MT_FTABLE);
+       if (t != NULL) {
+               atomic_add_32(&ipq_count, 1);
+               fp = mtod(t, struct ipq *);
+               bzero(fp, sizeof (*fp));
+       } else {
+               fp = NULL;
+       }
+       return (fp);
+}
+
+static void
+ipq_free(struct ipq *fp)
+{
+       (void) m_free(dtom(fp));
+       atomic_add_32(&ipq_count, -1);
 }
 
 /*
- * Drain off all datagram fragments.
+ * Drain callback
  */
 void
-ip_drain()
+ip_drain(void)
 {
-       int     i;
-
-       lck_mtx_lock(ip_mutex);
-       for (i = 0; i < IPREASS_NHASH; i++) {
-               while (ipq[i].next != &ipq[i]) {
-                       ipstat.ips_fragdropped += ipq[i].next->ipq_nfrags;
-                       ip_freef(ipq[i].next);
-               }
-       }
-       lck_mtx_unlock(ip_mutex);
-       in_rtqdrain();
+       frag_drain();           /* fragments */
+       in_rtqdrain();          /* protocol cloned routes */
+       in_arpdrain(NULL);      /* cloned routes: ARP */
 }
 
 /*
@@ -1523,15 +3137,21 @@ ip_drain()
  * 0 if the packet should be processed further.
  */
 static int
-ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop, struct route *ipforward_rt)
+ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop)
 {
-       register struct ip *ip = mtod(m, struct ip *);
-       register u_char *cp;
-       register struct ip_timestamp *ipt;
-       register struct in_ifaddr *ia;
+#pragma unused(pass)
+       struct ip *ip = mtod(m, struct ip *);
+       u_char *cp;
+       struct ip_timestamp *ipt;
+       struct in_ifaddr *ia;
        int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
        struct in_addr *sin, dst;
-       n_time ntime;
+       u_int32_t ntime;
+       struct sockaddr_in ipaddr = {
+           sizeof (ipaddr), AF_INET, 0, { 0 }, { 0, } };
+
+       /* Expect 32-bit aligned data pointer on strict-align platforms */
+       MBUF_STRICT_DATA_ALIGNMENT_CHECK_32(m);
 
        dst = ip->ip_dst;
        cp = (u_char *)(ip + 1);
@@ -1543,12 +3163,13 @@ ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop, struct rout
                if (opt == IPOPT_NOP)
                        optlen = 1;
                else {
-                       if (cnt < IPOPT_OLEN + sizeof(*cp)) {
+                       if (cnt < IPOPT_OLEN + sizeof (*cp)) {
                                code = &cp[IPOPT_OLEN] - (u_char *)ip;
                                goto bad;
                        }
                        optlen = cp[IPOPT_OLEN];
-                       if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) {
+                       if (optlen < IPOPT_OLEN + sizeof (*cp) ||
+                           optlen > cnt) {
                                code = &cp[IPOPT_OLEN] - (u_char *)ip;
                                goto bad;
                        }
@@ -1569,7 +3190,7 @@ ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop, struct rout
                 */
                case IPOPT_LSRR:
                case IPOPT_SSRR:
-                       if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
+                       if (optlen < IPOPT_OFFSET + sizeof (*cp)) {
                                code = &cp[IPOPT_OLEN] - (u_char *)ip;
                                goto bad;
                        }
@@ -1578,9 +3199,8 @@ ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop, struct rout
                                goto bad;
                        }
                        ipaddr.sin_addr = ip->ip_dst;
-                       ia = (struct in_ifaddr *)
-                               ifa_ifwithaddr((struct sockaddr *)&ipaddr);
-                       if (ia == 0) {
+                       ia = (struct in_ifaddr *)ifa_ifwithaddr(SA(&ipaddr));
+                       if (ia == NULL) {
                                if (opt == IPOPT_SSRR) {
                                        type = ICMP_UNREACH;
                                        code = ICMP_UNREACH_SRCFAIL;
@@ -1593,13 +3213,12 @@ ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop, struct rout
                                 * yet; nothing to do except forward.
                                 */
                                break;
-                       }
-                       else {
-                               ifafree(&ia->ia_ifa);
+                       } else {
+                               IFA_REMREF(&ia->ia_ifa);
                                ia = NULL;
                        }
                        off--;                  /* 0 origin */
-                       if (off > optlen - (int)sizeof(struct in_addr)) {
+                       if (off > optlen - (int)sizeof (struct in_addr)) {
                                /*
                                 * End of source route.  Should be for us.
                                 */
@@ -1618,17 +3237,21 @@ ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop, struct rout
                                         */
 nosourcerouting:
                                        log(LOG_WARNING,
-                                           "attempted source route from %s to %s\n",
-                                           inet_ntop(AF_INET, &ip->ip_src, buf, sizeof(buf)),
-                                           inet_ntop(AF_INET, &ip->ip_dst, buf2, sizeof(buf2)));
+                                           "attempted source route from %s "
+                                           "to %s\n",
+                                           inet_ntop(AF_INET, &ip->ip_src,
+                                           buf, sizeof (buf)),
+                                           inet_ntop(AF_INET, &ip->ip_dst,
+                                           buf2, sizeof (buf2)));
                                        type = ICMP_UNREACH;
                                        code = ICMP_UNREACH_SRCFAIL;
                                        goto bad;
                                } else {
                                        /*
-                                        * Not acting as a router, so silently drop.
+                                        * Not acting as a router,
+                                        * so silently drop.
                                         */
-                                       ipstat.ips_cantforward++;
+                                       OSAddAtomic(1, &ipstat.ips_cantforward);
                                        m_freem(m);
                                        return (1);
                                }
@@ -1637,29 +3260,31 @@ nosourcerouting:
                        /*
                         * locate outgoing interface
                         */
-                       (void)memcpy(&ipaddr.sin_addr, cp + off,
-                           sizeof(ipaddr.sin_addr));
+                       (void) memcpy(&ipaddr.sin_addr, cp + off,
+                           sizeof (ipaddr.sin_addr));
 
                        if (opt == IPOPT_SSRR) {
 #define        INA     struct in_ifaddr *
-#define        SA      struct sockaddr *
-                           if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) {
-                                       ia = (INA)ifa_ifwithnet((SA)&ipaddr);
+                               if ((ia = (INA)ifa_ifwithdstaddr(
+                                   SA(&ipaddr))) == NULL) {
+                                       ia = (INA)ifa_ifwithnet(SA(&ipaddr));
                                }
                        } else {
-                               ia = ip_rtaddr(ipaddr.sin_addr, ipforward_rt);
+                               ia = ip_rtaddr(ipaddr.sin_addr);
                        }
-                       if (ia == 0) {
+                       if (ia == NULL) {
                                type = ICMP_UNREACH;
                                code = ICMP_UNREACH_SRCFAIL;
                                goto bad;
                        }
                        ip->ip_dst = ipaddr.sin_addr;
-                       (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr),
-                           sizeof(struct in_addr));
-                       ifafree(&ia->ia_ifa);
+                       IFA_LOCK(&ia->ia_ifa);
+                       (void) memcpy(cp + off, &(IA_SIN(ia)->sin_addr),
+                           sizeof (struct in_addr));
+                       IFA_UNLOCK(&ia->ia_ifa);
+                       IFA_REMREF(&ia->ia_ifa);
                        ia = NULL;
-                       cp[IPOPT_OFFSET] += sizeof(struct in_addr);
+                       cp[IPOPT_OFFSET] += sizeof (struct in_addr);
                        /*
                         * Let ip_intr's mcast routing check handle mcast pkts
                         */
@@ -1667,7 +3292,7 @@ nosourcerouting:
                        break;
 
                case IPOPT_RR:
-                       if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
+                       if (optlen < IPOPT_OFFSET + sizeof (*cp)) {
                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                                goto bad;
                        }
@@ -1679,31 +3304,33 @@ nosourcerouting:
                         * If no space remains, ignore.
                         */
                        off--;                  /* 0 origin */
-                       if (off > optlen - (int)sizeof(struct in_addr))
+                       if (off > optlen - (int)sizeof (struct in_addr))
                                break;
-                       (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst,
-                           sizeof(ipaddr.sin_addr));
+                       (void) memcpy(&ipaddr.sin_addr, &ip->ip_dst,
+                           sizeof (ipaddr.sin_addr));
                        /*
                         * locate outgoing interface; if we're the destination,
                         * use the incoming interface (should be same).
                         */
-                       if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0) {
-                               if ((ia = ip_rtaddr(ipaddr.sin_addr, ipforward_rt)) == 0) {
+                       if ((ia = (INA)ifa_ifwithaddr(SA(&ipaddr))) == NULL) {
+                               if ((ia = ip_rtaddr(ipaddr.sin_addr)) == NULL) {
                                        type = ICMP_UNREACH;
                                        code = ICMP_UNREACH_HOST;
                                        goto bad;
                                }
                        }
-                       (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr),
-                           sizeof(struct in_addr));
-                       ifafree(&ia->ia_ifa);
+                       IFA_LOCK(&ia->ia_ifa);
+                       (void) memcpy(cp + off, &(IA_SIN(ia)->sin_addr),
+                           sizeof (struct in_addr));
+                       IFA_UNLOCK(&ia->ia_ifa);
+                       IFA_REMREF(&ia->ia_ifa);
                        ia = NULL;
-                       cp[IPOPT_OFFSET] += sizeof(struct in_addr);
+                       cp[IPOPT_OFFSET] += sizeof (struct in_addr);
                        break;
 
                case IPOPT_TS:
                        code = cp - (u_char *)ip;
-                       ipt = (struct ip_timestamp *)cp;
+                       ipt = (struct ip_timestamp *)(void *)cp;
                        if (ipt->ipt_len < 4 || ipt->ipt_len > 40) {
                                code = (u_char *)&ipt->ipt_len - (u_char *)ip;
                                goto bad;
@@ -1713,7 +3340,7 @@ nosourcerouting:
                                goto bad;
                        }
                        if (ipt->ipt_ptr >
-                           ipt->ipt_len - (int)sizeof(int32_t)) {
+                           ipt->ipt_len - (int)sizeof (int32_t)) {
                                if (++ipt->ipt_oflw == 0) {
                                        code = (u_char *)&ipt->ipt_ptr -
                                            (u_char *)ip;
@@ -1721,45 +3348,48 @@ nosourcerouting:
                                }
                                break;
                        }
-                       sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
+                       sin = (struct in_addr *)(void *)(cp + ipt->ipt_ptr - 1);
                        switch (ipt->ipt_flg) {
 
                        case IPOPT_TS_TSONLY:
                                break;
 
                        case IPOPT_TS_TSANDADDR:
-                               if (ipt->ipt_ptr - 1 + sizeof(n_time) +
-                                   sizeof(struct in_addr) > ipt->ipt_len) {
+                               if (ipt->ipt_ptr - 1 + sizeof (n_time) +
+                                   sizeof (struct in_addr) > ipt->ipt_len) {
                                        code = (u_char *)&ipt->ipt_ptr -
                                            (u_char *)ip;
                                        goto bad;
                                }
                                ipaddr.sin_addr = dst;
-                               ia = (INA)ifaof_ifpforaddr((SA)&ipaddr,
-                                                           m->m_pkthdr.rcvif);
-                               if (ia == 0)
+                               ia = (INA)ifaof_ifpforaddr(SA(&ipaddr),
+                                   m->m_pkthdr.rcvif);
+                               if (ia == NULL)
                                        continue;
-                               (void)memcpy(sin, &IA_SIN(ia)->sin_addr,
-                                   sizeof(struct in_addr));
-                               ipt->ipt_ptr += sizeof(struct in_addr);
-                               ifafree(&ia->ia_ifa);
+                               IFA_LOCK(&ia->ia_ifa);
+                               (void) memcpy(sin, &IA_SIN(ia)->sin_addr,
+                                   sizeof (struct in_addr));
+                               IFA_UNLOCK(&ia->ia_ifa);
+                               ipt->ipt_ptr += sizeof (struct in_addr);
+                               IFA_REMREF(&ia->ia_ifa);
                                ia = NULL;
                                break;
 
                        case IPOPT_TS_PRESPEC:
-                               if (ipt->ipt_ptr - 1 + sizeof(n_time) +
-                                   sizeof(struct in_addr) > ipt->ipt_len) {
+                               if (ipt->ipt_ptr - 1 + sizeof (n_time) +
+                                   sizeof (struct in_addr) > ipt->ipt_len) {
                                        code = (u_char *)&ipt->ipt_ptr -
                                            (u_char *)ip;
                                        goto bad;
                                }
-                               (void)memcpy(&ipaddr.sin_addr, sin,
-                                   sizeof(struct in_addr));
-                               if ((ia = (struct in_ifaddr*)ifa_ifwithaddr((SA)&ipaddr)) == 0)
+                               (void) memcpy(&ipaddr.sin_addr, sin,
+                                   sizeof (struct in_addr));
+                               if ((ia = (struct in_ifaddr *)ifa_ifwithaddr(
+                                   SA(&ipaddr))) == NULL)
                                        continue;
-                               ifafree(&ia->ia_ifa);
+                               IFA_REMREF(&ia->ia_ifa);
                                ia = NULL;
-                               ipt->ipt_ptr += sizeof(struct in_addr);
+                               ipt->ipt_ptr += sizeof (struct in_addr);
                                break;
 
                        default:
@@ -1769,60 +3399,113 @@ nosourcerouting:
                                goto bad;
                        }
                        ntime = iptime();
-                       (void)memcpy(cp + ipt->ipt_ptr - 1, &ntime,
-                           sizeof(n_time));
-                       ipt->ipt_ptr += sizeof(n_time);
+                       (void) memcpy(cp + ipt->ipt_ptr - 1, &ntime,
+                           sizeof (n_time));
+                       ipt->ipt_ptr += sizeof (n_time);
                }
        }
        if (forward && ipforwarding) {
-               ip_forward(m, 1, next_hop, ipforward_rt);
+               ip_forward(m, 1, next_hop);
                return (1);
        }
        return (0);
 bad:
-       ip->ip_len -= IP_VHL_HL(ip->ip_vhl) << 2;   /* XXX icmp_error adds in hdr length */
-       lck_mtx_unlock(ip_mutex);
        icmp_error(m, type, code, 0, 0);
-       lck_mtx_lock(ip_mutex);
-       ipstat.ips_badoptions++;
+       OSAddAtomic(1, &ipstat.ips_badoptions);
        return (1);
 }
 
 /*
- * Given address of next destination (final or next hop),
- * return internet address info of interface to be used to get there.
+ * Check for the presence of the IP Router Alert option [RFC2113]
+ * in the header of an IPv4 datagram.
+ *
+ * This call is not intended for use from the forwarding path; it is here
+ * so that protocol domains may check for the presence of the option.
+ * Given how FreeBSD's IPv4 stack is currently structured, the Router Alert
+ * option does not have much relevance to the implementation, though this
+ * may change in future.
+ * Router alert options SHOULD be passed if running in IPSTEALTH mode and
+ * we are not the endpoint.
+ * Length checks on individual options should already have been peformed
+ * by ip_dooptions() therefore they are folded under DIAGNOSTIC here.
+ *
+ * Return zero if not present or options are invalid, non-zero if present.
  */
-struct in_ifaddr *
-ip_rtaddr(dst, rt)
-       struct in_addr dst;
-       struct route *rt;
+int
+ip_checkrouteralert(struct mbuf *m)
 {
-       register struct sockaddr_in *sin;
-
-       sin = (struct sockaddr_in *)&rt->ro_dst;
+       struct ip *ip = mtod(m, struct ip *);
+       u_char *cp;
+       int opt, optlen, cnt, found_ra;
 
-       lck_mtx_lock(rt_mtx);
-       if (rt->ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr ||
-               rt->ro_rt->generation_id != route_generation) {
-               if (rt->ro_rt) {
-                       rtfree_locked(rt->ro_rt);
-                       rt->ro_rt = 0;
+       found_ra = 0;
+       cp = (u_char *)(ip + 1);
+       cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip);
+       for (; cnt > 0; cnt -= optlen, cp += optlen) {
+               opt = cp[IPOPT_OPTVAL];
+               if (opt == IPOPT_EOL)
+                       break;
+               if (opt == IPOPT_NOP)
+                       optlen = 1;
+               else {
+#ifdef DIAGNOSTIC
+                       if (cnt < IPOPT_OLEN + sizeof (*cp))
+                               break;
+#endif
+                       optlen = cp[IPOPT_OLEN];
+#ifdef DIAGNOSTIC
+                       if (optlen < IPOPT_OLEN + sizeof (*cp) || optlen > cnt)
+                               break;
+#endif
+               }
+               switch (opt) {
+               case IPOPT_RA:
+#ifdef DIAGNOSTIC
+                       if (optlen != IPOPT_OFFSET + sizeof (uint16_t) ||
+                           (*((uint16_t *)(void *)&cp[IPOPT_OFFSET]) != 0))
+                               break;
+                       else
+#endif
+                               found_ra = 1;
+                       break;
+               default:
+                       break;
                }
-               sin->sin_family = AF_INET;
-               sin->sin_len = sizeof(*sin);
-               sin->sin_addr = dst;
-
-               rtalloc_ign_locked(rt, RTF_PRCLONING);
        }
-       if (rt->ro_rt == 0) {
-               lck_mtx_unlock(rt_mtx);
-               return ((struct in_ifaddr *)0);
+
+       return (found_ra);
+}
+
+/*
+ * Given address of next destination (final or next hop),
+ * return internet address info of interface to be used to get there.
+ */
+struct in_ifaddr *
+ip_rtaddr(struct in_addr dst)
+{
+       struct sockaddr_in *sin;
+       struct ifaddr *rt_ifa;
+       struct route ro;
+
+       bzero(&ro, sizeof (ro));
+       sin = SIN(&ro.ro_dst);
+       sin->sin_family = AF_INET;
+       sin->sin_len = sizeof (*sin);
+       sin->sin_addr = dst;
+
+       rtalloc_ign(&ro, RTF_PRCLONING);
+       if (ro.ro_rt == NULL) {
+               ROUTE_RELEASE(&ro);
+               return (NULL);
        }
 
-       if (rt->ro_rt->rt_ifa)
-               ifaref(rt->ro_rt->rt_ifa);
-       lck_mtx_unlock(rt_mtx);
-       return ((struct in_ifaddr *) rt->ro_rt->rt_ifa);
+       RT_LOCK(ro.ro_rt);
+       if ((rt_ifa = ro.ro_rt->rt_ifa) != NULL)
+               IFA_ADDREF(rt_ifa);
+       RT_UNLOCK(ro.ro_rt);
+       ROUTE_RELEASE(&ro);
+
+       return ((struct in_ifaddr *)rt_ifa);
 }
 
 /*
@@ -1830,9 +3513,7 @@ ip_rtaddr(dst, rt)
  * to be picked up later by ip_srcroute if the receiver is interested.
  */
 void
-save_rte(option, dst)
-       u_char *option;
-       struct in_addr dst;
+save_rte(u_char *option, struct in_addr dst)
 {
        unsigned olen;
 
@@ -1841,10 +3522,10 @@ save_rte(option, dst)
        if (ipprintfs)
                printf("save_rte: olen %d\n", olen);
 #endif
-       if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
+       if (olen > sizeof (ip_srcrt) - (1 + sizeof (dst)))
                return;
        bcopy(option, ip_srcrt.srcopt, olen);
-       ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
+       ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof (struct in_addr);
        ip_srcrt.dst = dst;
 }
 
@@ -1854,22 +3535,23 @@ save_rte(option, dst)
  * The first hop is placed before the options, will be removed later.
  */
 struct mbuf *
-ip_srcroute()
+ip_srcroute(void)
 {
-       register struct in_addr *p, *q;
-       register struct mbuf *m;
+       struct in_addr *p, *q;
+       struct mbuf *m;
 
        if (ip_nhops == 0)
-               return ((struct mbuf *)0);
+               return (NULL);
+
        m = m_get(M_DONTWAIT, MT_HEADER);
-       if (m == 0)
-               return ((struct mbuf *)0);
+       if (m == NULL)
+               return (NULL);
 
-#define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
+#define        OPTSIZ  (sizeof (ip_srcrt.nop) + sizeof (ip_srcrt.srcopt))
 
        /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
-       m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
-           OPTSIZ;
+       m->m_len = ip_nhops * sizeof (struct in_addr) +
+           sizeof (struct in_addr) + OPTSIZ;
 #if DIAGNOSTIC
        if (ipprintfs)
                printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
@@ -1882,7 +3564,8 @@ ip_srcroute()
        *(mtod(m, struct in_addr *)) = *p--;
 #if DIAGNOSTIC
        if (ipprintfs)
-               printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr));
+               printf(" hops %lx",
+                   (u_int32_t)ntohl(mtod(m, struct in_addr *)->s_addr));
 #endif
 
        /*
@@ -1890,10 +3573,10 @@ ip_srcroute()
         */
        ip_srcrt.nop = IPOPT_NOP;
        ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
-       (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr),
+       (void) memcpy(mtod(m, caddr_t) + sizeof (struct in_addr),
            &ip_srcrt.nop, OPTSIZ);
-       q = (struct in_addr *)(mtod(m, caddr_t) +
-           sizeof(struct in_addr) + OPTSIZ);
+       q = (struct in_addr *)(void *)(mtod(m, caddr_t) +
+           sizeof (struct in_addr) + OPTSIZ);
 #undef OPTSIZ
        /*
         * Record return path as an IP source route,
@@ -1902,7 +3585,7 @@ ip_srcroute()
        while (p >= ip_srcrt.route) {
 #if DIAGNOSTIC
                if (ipprintfs)
-                       printf(" %lx", (u_long)ntohl(q->s_addr));
+                       printf(" %lx", (u_int32_t)ntohl(q->s_addr));
 #endif
                *q++ = *p--;
        }
@@ -1912,7 +3595,7 @@ ip_srcroute()
        *q = ip_srcrt.dst;
 #if DIAGNOSTIC
        if (ipprintfs)
-               printf(" %lx\n", (u_long)ntohl(q->s_addr));
+               printf(" %lx\n", (u_int32_t)ntohl(q->s_addr));
 #endif
        return (m);
 }
@@ -1925,15 +3608,17 @@ ip_srcroute()
  * XXX should be deleted; last arg currently ignored.
  */
 void
-ip_stripoptions(m, mopt)
-       register struct mbuf *m;
-       struct mbuf *mopt;
+ip_stripoptions(struct mbuf *m, struct mbuf *mopt)
 {
-       register int i;
+#pragma unused(mopt)
+       int i;
        struct ip *ip = mtod(m, struct ip *);
-       register caddr_t opts;
+       caddr_t opts;
        int olen;
 
+       /* Expect 32-bit aligned data pointer on strict-align platforms */
+       MBUF_STRICT_DATA_ALIGNMENT_CHECK_32(m);
+
        olen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip);
        opts = (caddr_t)(ip + 1);
        i = m->m_len - (sizeof (struct ip) + olen);
@@ -1941,18 +3626,87 @@ ip_stripoptions(m, mopt)
        m->m_len -= olen;
        if (m->m_flags & M_PKTHDR)
                m->m_pkthdr.len -= olen;
-       ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2);
+       ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof (struct ip) >> 2);
 }
 
 u_char inetctlerrmap[PRC_NCMDS] = {
        0,              0,              0,              0,
        0,              EMSGSIZE,       EHOSTDOWN,      EHOSTUNREACH,
-       EHOSTUNREACH,   EHOSTUNREACH,   ECONNREFUSED,   ECONNREFUSED,
+       ENETUNREACH,    EHOSTUNREACH,   ECONNREFUSED,   ECONNREFUSED,
        EMSGSIZE,       EHOSTUNREACH,   0,              0,
        0,              0,              0,              0,
        ENOPROTOOPT,    ECONNREFUSED
 };
 
+static int
+sysctl_ipforwarding SYSCTL_HANDLER_ARGS
+{
+#pragma unused(arg1, arg2)
+       int i, was_ipforwarding = ipforwarding;
+
+       i = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
+       if (i != 0 || req->newptr == USER_ADDR_NULL)
+               return (i);
+
+       if (was_ipforwarding && !ipforwarding) {
+               /* clean up IPv4 forwarding cached routes */
+               ifnet_head_lock_shared();
+               for (i = 0; i <= if_index; i++) {
+                       struct ifnet *ifp = ifindex2ifnet[i];
+                       if (ifp != NULL) {
+                               lck_mtx_lock(&ifp->if_cached_route_lock);
+                               ROUTE_RELEASE(&ifp->if_fwd_route);
+                               bzero(&ifp->if_fwd_route,
+                                   sizeof (ifp->if_fwd_route));
+                               lck_mtx_unlock(&ifp->if_cached_route_lock);
+                       }
+               }
+               ifnet_head_done();
+       }
+
+       return (0);
+}
+
+/*
+ * Similar to inp_route_{copyout,copyin} routines except that these copy
+ * out the cached IPv4 forwarding route from struct ifnet instead of the
+ * inpcb.  See comments for those routines for explanations.
+ */
+static void
+ip_fwd_route_copyout(struct ifnet *ifp, struct route *dst)
+{
+       struct route *src = &ifp->if_fwd_route;
+
+       lck_mtx_lock_spin(&ifp->if_cached_route_lock);
+       lck_mtx_convert_spin(&ifp->if_cached_route_lock);
+
+       /* Minor sanity check */
+       if (src->ro_rt != NULL && rt_key(src->ro_rt)->sa_family != AF_INET)
+               panic("%s: wrong or corrupted route: %p", __func__, src);
+
+       route_copyout(dst, src, sizeof (*dst));
+
+       lck_mtx_unlock(&ifp->if_cached_route_lock);
+}
+
+static void
+ip_fwd_route_copyin(struct ifnet *ifp, struct route *src)
+{
+       struct route *dst = &ifp->if_fwd_route;
+
+       lck_mtx_lock_spin(&ifp->if_cached_route_lock);
+       lck_mtx_convert_spin(&ifp->if_cached_route_lock);
+
+       /* Minor sanity check */
+       if (src->ro_rt != NULL && rt_key(src->ro_rt)->sa_family != AF_INET)
+               panic("%s: wrong or corrupted route: %p", __func__, src);
+
+       if (ifp->if_fwd_cacheok)
+               route_copyin(src, dst, sizeof (*src));
+
+       lck_mtx_unlock(&ifp->if_cached_route_lock);
+}
+
 /*
  * Forward a packet.  If some error occurs return the sender
  * an icmp packet.  Note we can't always generate a meaningful
@@ -1968,43 +3722,56 @@ u_char inetctlerrmap[PRC_NCMDS] = {
  * via a source route.
  */
 static void
-ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop, struct route *ipforward_rt)
+ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop)
 {
-       register struct ip *ip = mtod(m, struct ip *);
-       register struct sockaddr_in *sin;
-       register struct rtentry *rt;
+#if !IPFIREWALL
+#pragma unused(next_hop)
+#endif
+       struct ip *ip = mtod(m, struct ip *);
+       struct sockaddr_in *sin;
+       struct rtentry *rt;
+       struct route fwd_rt;
        int error, type = 0, code = 0;
        struct mbuf *mcopy;
        n_long dest;
        struct in_addr pkt_dst;
-       struct ifnet *destifp;
+       u_int32_t nextmtu = 0, len;
+       struct ip_out_args ipoa = { IFSCOPE_NONE, { 0 }, 0, 0 };
+       struct ifnet *rcvifp = m->m_pkthdr.rcvif;
 #if IPSEC
-       struct ifnet dummyifp;
-#endif
+       struct secpolicy *sp = NULL;
+       int ipsecerror;
+#endif /* IPSEC */
+#if PF
+       struct pf_mtag *pf_mtag;
+#endif /* PF */
 
        dest = 0;
+#if IPFIREWALL
        /*
         * Cache the destination address of the packet; this may be
         * changed by use of 'ipfw fwd'.
         */
-       pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst;
+       pkt_dst = ((next_hop != NULL) ? next_hop->sin_addr : ip->ip_dst);
+#else /* !IPFIREWALL */
+       pkt_dst = ip->ip_dst;
+#endif /* !IPFIREWALL */
 
 #if DIAGNOSTIC
        if (ipprintfs)
                printf("forward: src %lx dst %lx ttl %x\n",
-                   (u_long)ip->ip_src.s_addr, (u_long)pkt_dst.s_addr,
+                   (u_int32_t)ip->ip_src.s_addr, (u_int32_t)pkt_dst.s_addr,
                    ip->ip_ttl);
 #endif
 
-
-       if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(pkt_dst) == 0) {
-               ipstat.ips_cantforward++;
+       if (m->m_flags & (M_BCAST|M_MCAST) || !in_canforward(pkt_dst)) {
+               OSAddAtomic(1, &ipstat.ips_cantforward);
                m_freem(m);
                return;
        }
 #if IPSTEALTH
        if (!ipstealth) {
-#endif
+#endif /* IPSTEALTH */
                if (ip->ip_ttl <= IPTTLDEC) {
                        icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS,
                            dest, 0);
@@ -2012,27 +3779,33 @@ ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop, struct route
                }
 #if IPSTEALTH
        }
-#endif
+#endif /* IPSTEALTH */
+
+#if PF
+       pf_mtag = pf_find_mtag(m);
+       if (pf_mtag != NULL && pf_mtag->pftag_rtableid != IFSCOPE_NONE) {
+               ipoa.ipoa_boundif = pf_mtag->pftag_rtableid;
+               ipoa.ipoa_flags |= IPOAF_BOUND_IF;
+       }
+#endif /* PF */
+
+       ip_fwd_route_copyout(rcvifp, &fwd_rt);
+
+       sin = SIN(&fwd_rt.ro_dst);
+       if (ROUTE_UNUSABLE(&fwd_rt) || pkt_dst.s_addr != sin->sin_addr.s_addr) {
+               ROUTE_RELEASE(&fwd_rt);
 
-       sin = (struct sockaddr_in *)&ipforward_rt->ro_dst;
-       if ((rt = ipforward_rt->ro_rt) == 0 ||
-           pkt_dst.s_addr != sin->sin_addr.s_addr ||
-           ipforward_rt->ro_rt->generation_id != route_generation) {
-               if (ipforward_rt->ro_rt) {
-                       rtfree(ipforward_rt->ro_rt);
-                       ipforward_rt->ro_rt = 0;
-               }
                sin->sin_family = AF_INET;
-               sin->sin_len = sizeof(*sin);
+               sin->sin_len = sizeof (*sin);
                sin->sin_addr = pkt_dst;
 
-               rtalloc_ign(ipforward_rt, RTF_PRCLONING);
-               if (ipforward_rt->ro_rt == 0) {
+               rtalloc_scoped_ign(&fwd_rt, RTF_PRCLONING, ipoa.ipoa_boundif);
+               if (fwd_rt.ro_rt == NULL) {
                        icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
-                       return;
+                       goto done;
                }
-               rt = ipforward_rt->ro_rt;
        }
+       rt = fwd_rt.ro_rt;
 
        /*
         * Save the IP header and at most 8 bytes of the payload,
@@ -2053,11 +3826,11 @@ ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop, struct route
 
 #if IPSTEALTH
        if (!ipstealth) {
-#endif
+#endif /* IPSTEALTH */
                ip->ip_ttl -= IPTTLDEC;
 #if IPSTEALTH
        }
-#endif
+#endif /* IPSTEALTH */
 
        /*
         * If forwarding packet using same interface that it came in on,
@@ -2067,72 +3840,101 @@ ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop, struct route
         * Also, don't send redirect if forwarding using a default route
         * or a route modified by a redirect.
         */
-#define        satosin(sa)     ((struct sockaddr_in *)(sa))
+       RT_LOCK_SPIN(rt);
        if (rt->rt_ifp == m->m_pkthdr.rcvif &&
-           (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
-           satosin(rt_key(rt))->sin_addr.s_addr != 0 &&
-           ipsendredirects && !srcrt) {
-#define        RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa))
-               u_long src = ntohl(ip->ip_src.s_addr);
-
-               if (RTA(rt) &&
-                   (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) {
-                   if (rt->rt_flags & RTF_GATEWAY)
-                       dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
-                   else
-                       dest = pkt_dst.s_addr;
-                   /* Router requirements says to only send host redirects */
-                   type = ICMP_REDIRECT;
-                   code = ICMP_REDIRECT_HOST;
+           !(rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) &&
+           satosin(rt_key(rt))->sin_addr.s_addr != INADDR_ANY &&
+           ipsendredirects && !srcrt && rt->rt_ifa != NULL) {
+               struct in_ifaddr *ia = (struct in_ifaddr *)rt->rt_ifa;
+               u_int32_t src = ntohl(ip->ip_src.s_addr);
+
+               /* Become a regular mutex */
+               RT_CONVERT_LOCK(rt);
+               IFA_LOCK_SPIN(&ia->ia_ifa);
+               if ((src & ia->ia_subnetmask) == ia->ia_subnet) {
+                       if (rt->rt_flags & RTF_GATEWAY)
+                               dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
+                       else
+                               dest = pkt_dst.s_addr;
+                       /*
+                        * Router requirements says to only send
+                        * host redirects.
+                        */
+                       type = ICMP_REDIRECT;
+                       code = ICMP_REDIRECT_HOST;
 #if DIAGNOSTIC
-                   if (ipprintfs)
-                       printf("redirect (%d) to %lx\n", code, (u_long)dest);
+                       if (ipprintfs)
+                               printf("redirect (%d) to %lx\n", code,
+                                   (u_int32_t)dest);
 #endif
                }
+               IFA_UNLOCK(&ia->ia_ifa);
        }
+       RT_UNLOCK(rt);
 
-    {
-       if (next_hop) {
+#if IPFIREWALL
+       if (next_hop != NULL) {
                /* Pass IPFORWARD info if available */
                struct m_tag *tag;
-               struct ip_fwd_tag       *ipfwd_tag;
-               
-               tag = m_tag_alloc(KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_IPFORWARD,
-                               sizeof(struct sockaddr_in), M_NOWAIT);
+               struct ip_fwd_tag *ipfwd_tag;
+
+               tag = m_tag_create(KERNEL_MODULE_TAG_ID,
+                   KERNEL_TAG_TYPE_IPFORWARD,
+                   sizeof (*ipfwd_tag), M_NOWAIT, m);
                if (tag == NULL) {
                        error = ENOBUFS;
                        m_freem(m);
-                       return;
+                       goto done;
                }
-               
+
                ipfwd_tag = (struct ip_fwd_tag *)(tag+1);
                ipfwd_tag->next_hop = next_hop;
 
                m_tag_prepend(m, tag);
        }
-       error = ip_output_list(m, 0, (struct mbuf *)0, ipforward_rt, 
-                         IP_FORWARDING, 0);
-    }
-       if (error)
-               ipstat.ips_cantforward++;
-       else {
-               ipstat.ips_forward++;
-               if (type)
-                       ipstat.ips_redirectsent++;
-               else {
-                       if (mcopy) {
-                               ipflow_create(ipforward_rt, mcopy);
+#endif /* IPFIREWALL */
+
+       /* Mark this packet as being forwarded from another interface */
+       m->m_pkthdr.pkt_flags |= PKTF_FORWARDED;
+       len = m_pktlen(m);
+
+       error = ip_output(m, NULL, &fwd_rt, IP_FORWARDING | IP_OUTARGS,
+           NULL, &ipoa);
+
+       /* Refresh rt since the route could have changed while in IP */
+       rt = fwd_rt.ro_rt;
+
+       if (error != 0) {
+               OSAddAtomic(1, &ipstat.ips_cantforward);
+       } else {
+               /*
+                * Increment stats on the source interface; the ones
+                * for destination interface has been taken care of
+                * during output above by virtue of PKTF_FORWARDED.
+                */
+               rcvifp->if_fpackets++;
+               rcvifp->if_fbytes += len;
+
+               OSAddAtomic(1, &ipstat.ips_forward);
+               if (type != 0) {
+                       OSAddAtomic(1, &ipstat.ips_redirectsent);
+               } else {
+                       if (mcopy != NULL) {
+                               /*
+                                * If we didn't have to go thru ipflow and
+                                * the packet was successfully consumed by
+                                * ip_output, the mcopy is rather a waste;
+                                * this could be further optimized.
+                                */
                                m_freem(mcopy);
                        }
-                       return;
+                       goto done;
                }
        }
        if (mcopy == NULL)
-               return;
-       destifp = NULL;
+               goto done;
 
        switch (error) {
-
        case 0:                         /* forwarded, but need redirect */
                /* type, code set above */
                break;
@@ -2149,205 +3951,461 @@ ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop, struct route
        case EMSGSIZE:
                type = ICMP_UNREACH;
                code = ICMP_UNREACH_NEEDFRAG;
-#ifndef IPSEC
-               if (ipforward_rt->ro_rt)
-                       destifp = ipforward_rt->ro_rt->rt_ifp;
-#else
+
+               if (rt == NULL) {
+                       break;
+               } else {
+                       RT_LOCK_SPIN(rt);
+                       if (rt->rt_ifp != NULL)
+                               nextmtu = rt->rt_ifp->if_mtu;
+                       RT_UNLOCK(rt);
+               }
+#ifdef IPSEC
+               if (ipsec_bypass)
+                       break;
+
                /*
                 * If the packet is routed over IPsec tunnel, tell the
                 * originator the tunnel MTU.
                 *      tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
                 * XXX quickhack!!!
                 */
-               if (ipforward_rt->ro_rt) {
-                       struct secpolicy *sp = NULL;
-                       int ipsecerror;
-                       int ipsechdr;
+               sp = ipsec4_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND,
+                   IP_FORWARDING, &ipsecerror);
+
+               if (sp == NULL)
+                       break;
+
+               /*
+                * find the correct route for outer IPv4
+                * header, compute tunnel MTU.
+                */
+               nextmtu = 0;
+
+               if (sp->req != NULL &&
+                   sp->req->saidx.mode == IPSEC_MODE_TUNNEL) {
+                       struct secasindex saidx;
+                       struct secasvar *sav;
                        struct route *ro;
+                       struct ip *ipm;
+                       int ipsechdr;
 
-                       if (ipsec_bypass) {
-                               destifp = ipforward_rt->ro_rt->rt_ifp;
-                               ipstat.ips_cantfrag++;
-                               break;
+                       /* count IPsec header size */
+                       ipsechdr = ipsec_hdrsiz(sp);
+
+                       ipm = mtod(mcopy, struct ip *);
+                       bcopy(&sp->req->saidx, &saidx, sizeof (saidx));
+                       saidx.mode = sp->req->saidx.mode;
+                       saidx.reqid = sp->req->saidx.reqid;
+                       sin = SIN(&saidx.src);
+                       if (sin->sin_len == 0) {
+                               sin->sin_len = sizeof (*sin);
+                               sin->sin_family = AF_INET;
+                               sin->sin_port = IPSEC_PORT_ANY;
+                               bcopy(&ipm->ip_src, &sin->sin_addr,
+                                   sizeof (sin->sin_addr));
                        }
-                       lck_mtx_lock(sadb_mutex);
-                       sp = ipsec4_getpolicybyaddr(mcopy,
-                                                   IPSEC_DIR_OUTBOUND,
-                                                   IP_FORWARDING,
-                                                   &ipsecerror);
-
-                       if (sp == NULL)
-                               destifp = ipforward_rt->ro_rt->rt_ifp;
-                       else {
-                               /* count IPsec header size */
-                               ipsechdr = ipsec4_hdrsiz(mcopy,
-                                                        IPSEC_DIR_OUTBOUND,
-                                                        NULL);
-
-                               /*
-                                * find the correct route for outer IPv4
-                                * header, compute tunnel MTU.
-                                *
-                                * XXX BUG ALERT
-                                * The "dummyifp" code relies upon the fact
-                                * that icmp_error() touches only ifp->if_mtu.
-                                */
-                               /*XXX*/
-                               destifp = NULL;
-                               if (sp->req != NULL
-                                && sp->req->sav != NULL
-                                && sp->req->sav->sah != NULL) {
-                                       ro = &sp->req->sav->sah->sa_route;
-                                       if (ro->ro_rt && ro->ro_rt->rt_ifp) {
-                                               dummyifp.if_mtu =
-                                                   ro->ro_rt->rt_ifp->if_mtu;
-                                               dummyifp.if_mtu -= ipsechdr;
-                                               destifp = &dummyifp;
+                       sin = SIN(&saidx.dst);
+                       if (sin->sin_len == 0) {
+                               sin->sin_len = sizeof (*sin);
+                               sin->sin_family = AF_INET;
+                               sin->sin_port = IPSEC_PORT_ANY;
+                               bcopy(&ipm->ip_dst, &sin->sin_addr,
+                                   sizeof (sin->sin_addr));
+                       }
+                       sav = key_allocsa_policy(&saidx);
+                       if (sav != NULL) {
+                               lck_mtx_lock(sadb_mutex);
+                               if (sav->sah != NULL) {
+                                       ro = &sav->sah->sa_route;
+                                       if (ro->ro_rt != NULL) {
+                                               RT_LOCK(ro->ro_rt);
+                                               if (ro->ro_rt->rt_ifp != NULL) {
+                                                       nextmtu = ro->ro_rt->
+                                                           rt_ifp->if_mtu;
+                                                       nextmtu -= ipsechdr;
+                                               }
+                                               RT_UNLOCK(ro->ro_rt);
                                        }
                                }
-
-                               key_freesp(sp);
+                               key_freesav(sav, KEY_SADB_LOCKED);
+                               lck_mtx_unlock(sadb_mutex);
                        }
-                       lck_mtx_unlock(sadb_mutex);
                }
-#endif /*IPSEC*/
-               ipstat.ips_cantfrag++;
+               key_freesp(sp, KEY_SADB_UNLOCKED);
+#endif /* IPSEC */
                break;
 
        case ENOBUFS:
-               type = ICMP_SOURCEQUENCH;
-               code = 0;
+               /*
+                * A router should not generate ICMP_SOURCEQUENCH as
+                * required in RFC1812 Requirements for IP Version 4 Routers.
+                * Source quench could be a big problem under DoS attacks,
+                * or if the underlying interface is rate-limited.
+                * Those who need source quench packets may re-enable them
+                * via the net.inet.ip.sendsourcequench sysctl.
+                */
+               if (ip_sendsourcequench == 0) {
+                       m_freem(mcopy);
+                       goto done;
+               } else {
+                       type = ICMP_SOURCEQUENCH;
+                       code = 0;
+               }
                break;
 
        case EACCES:                    /* ipfw denied packet */
                m_freem(mcopy);
-               return;
+               goto done;
        }
-       icmp_error(mcopy, type, code, dest, destifp);
+
+       if (type == ICMP_UNREACH && code == ICMP_UNREACH_NEEDFRAG)
+               OSAddAtomic(1, &ipstat.ips_cantfrag);
+
+       icmp_error(mcopy, type, code, dest, nextmtu);
+done:
+       ip_fwd_route_copyin(rcvifp, &fwd_rt);
 }
 
-void
-ip_savecontrol(
-       register struct inpcb *inp,
-       register struct mbuf **mp,
-       register struct ip *ip,
-       register struct mbuf *m)
+int
+ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip,
+    struct mbuf *m)
 {
+       *mp = NULL;
        if (inp->inp_socket->so_options & SO_TIMESTAMP) {
                struct timeval tv;
 
-               microtime(&tv);
-               *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
-                       SCM_TIMESTAMP, SOL_SOCKET);
-               if (*mp)
-                       mp = &(*mp)->m_next;
+               getmicrotime(&tv);
+               mp = sbcreatecontrol_mbuf((caddr_t)&tv, sizeof (tv),
+                   SCM_TIMESTAMP, SOL_SOCKET, mp);
+               if (*mp == NULL) {
+                       goto no_mbufs;
+               }
+       }
+       if (inp->inp_socket->so_options & SO_TIMESTAMP_MONOTONIC) {
+               uint64_t time;
+
+               time = mach_absolute_time();
+               mp = sbcreatecontrol_mbuf((caddr_t)&time, sizeof (time),
+                   SCM_TIMESTAMP_MONOTONIC, SOL_SOCKET, mp);
+               if (*mp == NULL) {
+                       goto no_mbufs;
+               }
        }
        if (inp->inp_flags & INP_RECVDSTADDR) {
-               *mp = sbcreatecontrol((caddr_t) &ip->ip_dst,
-                   sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
-               if (*mp)
-                       mp = &(*mp)->m_next;
+               mp = sbcreatecontrol_mbuf((caddr_t)&ip->ip_dst,
+                   sizeof (struct in_addr), IP_RECVDSTADDR, IPPROTO_IP, mp);
+               if (*mp == NULL) {
+                       goto no_mbufs;
+               }
        }
 #ifdef notyet
-       /* XXX
+       /*
+        * XXX
         * Moving these out of udp_input() made them even more broken
         * than they already were.
         */
        /* options were tossed already */
        if (inp->inp_flags & INP_RECVOPTS) {
-               *mp = sbcreatecontrol((caddr_t) opts_deleted_above,
-                   sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP);
-               if (*mp)
-                       mp = &(*mp)->m_next;
+               mp = sbcreatecontrol_mbuf((caddr_t)opts_deleted_above,
+                   sizeof (struct in_addr), IP_RECVOPTS, IPPROTO_IP, mp);
+               if (*mp == NULL) {
+                       goto no_mbufs;
+               }
        }
        /* ip_srcroute doesn't do what we want here, need to fix */
        if (inp->inp_flags & INP_RECVRETOPTS) {
-               *mp = sbcreatecontrol((caddr_t) ip_srcroute(),
-                   sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP);
-               if (*mp)
-                       mp = &(*mp)->m_next;
+               mp = sbcreatecontrol_mbuf((caddr_t)ip_srcroute(),
+                   sizeof (struct in_addr), IP_RECVRETOPTS, IPPROTO_IP, mp);
+               if (*mp == NULL) {
+                       goto no_mbufs;
+               }
        }
-#endif
+#endif /* notyet */
        if (inp->inp_flags & INP_RECVIF) {
                struct ifnet *ifp;
-               struct sdlbuf {
-                       struct sockaddr_dl sdl;
-                       u_char  pad[32];
-               } sdlbuf;
-               struct sockaddr_dl *sdp;
-               struct sockaddr_dl *sdl2 = &sdlbuf.sdl;
+               uint8_t sdlbuf[SOCK_MAXADDRLEN + 1];
+               struct sockaddr_dl *sdl2 = SDL(&sdlbuf);
+
+               /*
+                * Make sure to accomodate the largest possible
+                * size of SA(if_lladdr)->sa_len.
+                */
+               _CASSERT(sizeof (sdlbuf) == (SOCK_MAXADDRLEN + 1));
 
                ifnet_head_lock_shared();
-               if (((ifp = m->m_pkthdr.rcvif)) 
-               && ( ifp->if_index && (ifp->if_index <= if_index))) {
+               if ((ifp = m->m_pkthdr.rcvif) != NULL &&
+                   ifp->if_index && (ifp->if_index <= if_index)) {
                        struct ifaddr *ifa = ifnet_addrs[ifp->if_index - 1];
-                       
+                       struct sockaddr_dl *sdp;
+
                        if (!ifa || !ifa->ifa_addr)
                                goto makedummy;
-                       
-                       sdp = (struct sockaddr_dl *)ifa->ifa_addr;
+
+                       IFA_LOCK_SPIN(ifa);
+                       sdp = SDL(ifa->ifa_addr);
                        /*
                         * Change our mind and don't try copy.
                         */
-                       if ((sdp->sdl_family != AF_LINK)
-                       || (sdp->sdl_len > sizeof(sdlbuf))) {
+                       if (sdp->sdl_family != AF_LINK) {
+                               IFA_UNLOCK(ifa);
                                goto makedummy;
                        }
+                       /* the above _CASSERT ensures sdl_len fits in sdlbuf */
                        bcopy(sdp, sdl2, sdp->sdl_len);
+                       IFA_UNLOCK(ifa);
                } else {
-makedummy:     
-                       sdl2->sdl_len
-                               = offsetof(struct sockaddr_dl, sdl_data[0]);
+makedummy:
+                       sdl2->sdl_len =
+                           offsetof(struct sockaddr_dl, sdl_data[0]);
                        sdl2->sdl_family = AF_LINK;
                        sdl2->sdl_index = 0;
                        sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0;
                }
                ifnet_head_done();
-               *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len,
-                       IP_RECVIF, IPPROTO_IP);
-               if (*mp)
-                       mp = &(*mp)->m_next;
+               mp = sbcreatecontrol_mbuf((caddr_t)sdl2, sdl2->sdl_len,
+                   IP_RECVIF, IPPROTO_IP, mp);
+               if (*mp == NULL) {
+                       goto no_mbufs;
+               }
        }
        if (inp->inp_flags & INP_RECVTTL) {
-               *mp = sbcreatecontrol((caddr_t)&ip->ip_ttl, sizeof(ip->ip_ttl), IP_RECVTTL, IPPROTO_IP);
-               if (*mp) mp = &(*mp)->m_next;
+               mp = sbcreatecontrol_mbuf((caddr_t)&ip->ip_ttl,
+                   sizeof (ip->ip_ttl), IP_RECVTTL, IPPROTO_IP, mp);
+               if (*mp == NULL) {
+                       goto no_mbufs;
+               }
        }
+       if (inp->inp_socket->so_flags & SOF_RECV_TRAFFIC_CLASS) {
+               int tc = m_get_traffic_class(m);
+
+               mp = sbcreatecontrol_mbuf((caddr_t)&tc, sizeof (tc),
+                   SO_TRAFFIC_CLASS, SOL_SOCKET, mp);
+               if (*mp == NULL) {
+                       goto no_mbufs;
+               }
+       }
+       if (inp->inp_flags & INP_PKTINFO) {
+               struct in_pktinfo pi;
+
+               bzero(&pi, sizeof (struct in_pktinfo));
+               bcopy(&ip->ip_dst, &pi.ipi_addr, sizeof (struct in_addr));
+               pi.ipi_ifindex = (m != NULL && m->m_pkthdr.rcvif != NULL) ?
+                   m->m_pkthdr.rcvif->if_index : 0;
+
+               mp = sbcreatecontrol_mbuf((caddr_t)&pi,
+                   sizeof (struct in_pktinfo), IP_RECVPKTINFO, IPPROTO_IP, mp);
+               if (*mp == NULL) {
+                       goto no_mbufs;
+               }
+       }
+       return (0);
+
+no_mbufs:
+       ipstat.ips_pktdropcntrl++;
+       return (ENOBUFS);
 }
 
-int
-ip_rsvp_init(struct socket *so)
+static inline u_short
+ip_cksum(struct mbuf *m, int hlen)
+{
+       u_short sum;
+
+       if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
+               sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
+       } else if (!(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) &&
+           !(m->m_pkthdr.pkt_flags & PKTF_LOOP)) {
+               /*
+                * The packet arrived on an interface which isn't capable
+                * of performing IP header checksum; compute it now.
+                */
+               sum = ip_cksum_hdr_in(m, hlen);
+       } else {
+               sum = 0;
+               m->m_pkthdr.csum_flags |= (CSUM_DATA_VALID | CSUM_PSEUDO_HDR |
+                   CSUM_IP_CHECKED | CSUM_IP_VALID);
+               m->m_pkthdr.csum_data = 0xffff;
+       }
+
+       if (sum != 0)
+               OSAddAtomic(1, &ipstat.ips_badsum);
+
+       return (sum);
+}
+
+static int
+ip_getstat SYSCTL_HANDLER_ARGS
+{
+#pragma unused(oidp, arg1, arg2)
+       if (req->oldptr == USER_ADDR_NULL)
+               req->oldlen = (size_t)sizeof (struct ipstat);
+
+       return (SYSCTL_OUT(req, &ipstat, MIN(sizeof (ipstat), req->oldlen)));
+}
+
+void
+ip_setsrcifaddr_info(struct mbuf *m, uint32_t src_idx, struct in_ifaddr *ia)
 {
-       if (so->so_type != SOCK_RAW ||
-           so->so_proto->pr_protocol != IPPROTO_RSVP)
-         return EOPNOTSUPP;
+       VERIFY(m->m_flags & M_PKTHDR);
+
+       /*
+        * If the source ifaddr is specified, pick up the information
+        * from there; otherwise just grab the passed-in ifindex as the
+        * caller may not have the ifaddr available.
+        */
+       if (ia != NULL) {
+               m->m_pkthdr.pkt_flags |= PKTF_IFAINFO;
+               m->m_pkthdr.src_ifindex = ia->ia_ifp->if_index;
+       } else {
+               m->m_pkthdr.src_ifindex = src_idx;
+               if (src_idx != 0)
+                       m->m_pkthdr.pkt_flags |= PKTF_IFAINFO;
+       }
+}
 
-       if (ip_rsvpd != NULL)
-         return EADDRINUSE;
+void
+ip_setdstifaddr_info(struct mbuf *m, uint32_t dst_idx, struct in_ifaddr *ia)
+{
+       VERIFY(m->m_flags & M_PKTHDR);
 
-       ip_rsvpd = so;
        /*
-        * This may seem silly, but we need to be sure we don't over-increment
-        * the RSVP counter, in case something slips up.
+        * If the destination ifaddr is specified, pick up the information
+        * from there; otherwise just grab the passed-in ifindex as the
+        * caller may not have the ifaddr available.
         */
-       if (!ip_rsvp_on) {
-               ip_rsvp_on = 1;
-               rsvp_on++;
+       if (ia != NULL) {
+               m->m_pkthdr.pkt_flags |= PKTF_IFAINFO;
+               m->m_pkthdr.dst_ifindex = ia->ia_ifp->if_index;
+       } else {
+               m->m_pkthdr.dst_ifindex = dst_idx;
+               if (dst_idx != 0)
+                       m->m_pkthdr.pkt_flags |= PKTF_IFAINFO;
        }
+}
+
+int
+ip_getsrcifaddr_info(struct mbuf *m, uint32_t *src_idx, uint32_t *iaf)
+{
+       VERIFY(m->m_flags & M_PKTHDR);
+
+       if (!(m->m_pkthdr.pkt_flags & PKTF_IFAINFO))
+               return (-1);
+
+       if (src_idx != NULL)
+               *src_idx = m->m_pkthdr.src_ifindex;
 
-       return 0;
+       if (iaf != NULL)
+               *iaf = 0;
+
+       return (0);
 }
 
 int
-ip_rsvp_done(void)
+ip_getdstifaddr_info(struct mbuf *m, uint32_t *dst_idx, uint32_t *iaf)
+{
+       VERIFY(m->m_flags & M_PKTHDR);
+
+       if (!(m->m_pkthdr.pkt_flags & PKTF_IFAINFO))
+               return (-1);
+
+       if (dst_idx != NULL)
+               *dst_idx = m->m_pkthdr.dst_ifindex;
+
+       if (iaf != NULL)
+               *iaf = 0;
+
+       return (0);
+}
+
+/*
+ * Protocol input handler for IPPROTO_GRE.
+ */
+void
+gre_input(struct mbuf *m, int off)
 {
-       ip_rsvpd = NULL;
+       gre_input_func_t fn = gre_input_func;
+
+       /*
+        * If there is a registered GRE input handler, pass mbuf to it.
+        */
+       if (fn != NULL) {
+               lck_mtx_unlock(inet_domain_mutex);
+               m = fn(m, off, (mtod(m, struct ip *))->ip_p);
+               lck_mtx_lock(inet_domain_mutex);
+       }
+
        /*
-        * This may seem silly, but we need to be sure we don't over-decrement
-        * the RSVP counter, in case something slips up.
+        * If no matching tunnel that is up is found, we inject
+        * the mbuf to raw ip socket to see if anyone picks it up.
         */
-       if (ip_rsvp_on) {
-               ip_rsvp_on = 0;
-               rsvp_on--;
+       if (m != NULL)
+               rip_input(m, off);
+}
+
+/*
+ * Private KPI for PPP/PPTP.
+ */
+int
+ip_gre_register_input(gre_input_func_t fn)
+{
+       lck_mtx_lock(inet_domain_mutex);
+       gre_input_func = fn;
+       lck_mtx_unlock(inet_domain_mutex);
+
+       return (0);
+}
+
+static int
+sysctl_reset_ip_input_stats SYSCTL_HANDLER_ARGS
+{
+#pragma unused(arg1, arg2)
+       int error, i;
+
+       i = ip_input_measure;
+       error = sysctl_handle_int(oidp, &i, 0, req);
+       if (error || req->newptr == USER_ADDR_NULL)
+               goto done;
+       /* impose bounds */
+       if (i < 0 || i > 1) {
+               error = EINVAL;
+               goto done;
+       }
+       if (ip_input_measure != i && i == 1) {
+               net_perf_initialize(&net_perf, ip_input_measure_bins);
+       }
+       ip_input_measure = i;
+done:
+       return (error);
+}
+
+static int
+sysctl_ip_input_measure_bins SYSCTL_HANDLER_ARGS
+{
+#pragma unused(arg1, arg2)
+       int error;
+       uint64_t i;
+
+       i = ip_input_measure_bins;
+       error = sysctl_handle_quad(oidp, &i, 0, req);
+       if (error || req->newptr == USER_ADDR_NULL)
+               goto done;
+       /* validate data */
+       if (!net_perf_validate_bins(i)) {
+               error = EINVAL;
+               goto done;
        }
-       return 0;
+       ip_input_measure_bins = i;
+done:
+       return (error);
+}
+
+static int
+sysctl_ip_input_getperf SYSCTL_HANDLER_ARGS
+{
+#pragma unused(oidp, arg1, arg2)
+       if (req->oldptr == USER_ADDR_NULL)
+               req->oldlen = (size_t)sizeof (struct ipstat);
+
+       return (SYSCTL_OUT(req, &net_perf, MIN(sizeof (net_perf), req->oldlen)));
 }
+